diff --git a/qinling/api/controllers/v1/function.py b/qinling/api/controllers/v1/function.py
index 328d3ef2..396e09b9 100644
--- a/qinling/api/controllers/v1/function.py
+++ b/qinling/api/controllers/v1/function.py
@@ -129,7 +129,6 @@ class FunctionsController(rest.RestController):
             pecan.response.headers['Content-Disposition'] = (
                 'attachment; filename="%s"' % os.path.basename(func_db.name)
             )
-            LOG.info("Downloaded function %s", id)
 
     @rest_utils.wrap_pecan_controller_exception
     @pecan.expose('json')
diff --git a/qinling/api/controllers/v1/function_version.py b/qinling/api/controllers/v1/function_version.py
index bb07959f..0ce35ff6 100644
--- a/qinling/api/controllers/v1/function_version.py
+++ b/qinling/api/controllers/v1/function_version.py
@@ -12,10 +12,15 @@
 #    See the License for the specific language governing permissions and
 #    limitations under the License.
 
+import collections
+
 from oslo_config import cfg
 from oslo_log import log as logging
+from oslo_utils import strutils
+import pecan
 from pecan import rest
 import tenacity
+from webob.static import FileIter
 import wsmeext.pecan as wsme_pecan
 
 from qinling.api import access_control as acl
@@ -137,3 +142,38 @@ class FunctionVersionsController(rest.RestController):
                     for v in db_versions]
 
         return resources.FunctionVersions(function_versions=versions)
+
+    @rest_utils.wrap_pecan_controller_exception
+    @pecan.expose()
+    def get(self, function_id, version):
+        ctx = context.get_ctx()
+        acl.enforce('function_version:get', ctx)
+
+        download = strutils.bool_from_string(
+            pecan.request.GET.get('download', False)
+        )
+        version = int(version)
+
+        version_db = db_api.get_function_version(function_id, version)
+
+        if not download:
+            LOG.info("Getting version %s for function %s.", version,
+                     function_id)
+            pecan.override_template('json')
+            return resources.FunctionVersion.from_dict(
+                version_db.to_dict()).to_dict()
+
+        LOG.info("Downloading version %s for function %s.", version,
+                 function_id)
+
+        f = self.storage_provider.retrieve(ctx.projectid, function_id,
+                                           None, version=version)
+
+        if isinstance(f, collections.Iterable):
+            pecan.response.app_iter = f
+        else:
+            pecan.response.app_iter = FileIter(f)
+        pecan.response.headers['Content-Type'] = 'application/zip'
+        pecan.response.headers['Content-Disposition'] = (
+            'attachment; filename="%s_%s"' % (function_id, version)
+        )
diff --git a/qinling/db/api.py b/qinling/db/api.py
index dc376b7e..d9a362d7 100644
--- a/qinling/db/api.py
+++ b/qinling/db/api.py
@@ -206,3 +206,7 @@ def delete_webhooks(**kwargs):
 def increase_function_version(function_id, old_version, **kwargs):
     """This function is meant to be invoked within locking section."""
     return IMPL.increase_function_version(function_id, old_version, **kwargs)
+
+
+def get_function_version(function_id, version):
+    return IMPL.get_function_version(function_id, version)
diff --git a/qinling/db/sqlalchemy/api.py b/qinling/db/sqlalchemy/api.py
index e0e23369..c17ce8ca 100644
--- a/qinling/db/sqlalchemy/api.py
+++ b/qinling/db/sqlalchemy/api.py
@@ -514,3 +514,16 @@ def increase_function_version(function_id, old_version, session=None,
         )
 
     return version
+
+
+@db_base.session_aware()
+def get_function_version(function_id, version, session=None):
+    version_db = _secure_query(models.FunctionVersion).filter_by(
+        function_id=function_id, version_number=version).first()
+    if not version_db:
+        raise exc.DBEntityNotFoundError(
+            "FunctionVersion not found [function_id=%s, version_number=%s]" %
+            (function_id, version)
+        )
+
+    return version_db
diff --git a/qinling/storage/base.py b/qinling/storage/base.py
index ad345abc..299c536d 100644
--- a/qinling/storage/base.py
+++ b/qinling/storage/base.py
@@ -40,12 +40,13 @@ class PackageStorage(object):
         raise NotImplementedError
 
     @abc.abstractmethod
-    def retrieve(self, project_id, function, md5sum):
+    def retrieve(self, project_id, function, md5sum, version=None):
         """Get function package data.
 
         :param project_id: Project ID.
         :param function: Function ID.
         :param md5sum: The function MD5.
+        :param version: Optional. The function version number.
         :return: File descriptor that needs to close outside.
         """
         raise NotImplementedError
diff --git a/qinling/storage/file_system.py b/qinling/storage/file_system.py
index dc47ffbc..6969952d 100644
--- a/qinling/storage/file_system.py
+++ b/qinling/storage/file_system.py
@@ -74,23 +74,42 @@ class FileSystemStorage(base.PackageStorage):
         os.rename(new_func_zip, func_zip)
         return md5_actual
 
-    def retrieve(self, project_id, function, md5sum):
+    def retrieve(self, project_id, function, md5sum, version=0):
         """Get function package data.
 
+        If version is not 0, return the package data of that specific function
+        version.
+
         :param project_id: Project ID.
         :param function: Function ID.
         :param md5sum: The function MD5.
+        :param version: Optional. The function version number.
         :return: File descriptor that needs to close outside.
         """
         LOG.debug(
-            'Getting package data, function: %s, md5sum: %s, project: %s',
-            function, md5sum, project_id
+            'Getting package data, function: %s, version: %s, md5sum: %s, '
+            'project: %s',
+            function, md5sum, version, project_id
         )
 
-        func_zip = os.path.join(
-            self.base_path,
-            PACKAGE_PATH_TEMPLATE % (project_id, function, md5sum)
-        )
+        if version != 0:
+            project_dir = os.path.join(self.base_path, project_id)
+            for filename in os.listdir(project_dir):
+                root, ext = os.path.splitext(filename)
+                if (root.startswith("%s_%d" % (function, version))
+                        and ext == '.zip'):
+                    func_zip = os.path.join(project_dir, filename)
+                    break
+            else:
+                raise exc.StorageNotFoundException(
+                    'Package of version %d function %s for project %s not '
+                    'found.' % (version, function, project_id)
+                )
+        else:
+            func_zip = os.path.join(
+                self.base_path,
+                PACKAGE_PATH_TEMPLATE % (project_id, function, md5sum)
+            )
 
         if not os.path.exists(func_zip):
             raise exc.StorageNotFoundException(
@@ -99,7 +118,8 @@ class FileSystemStorage(base.PackageStorage):
             )
 
         f = open(func_zip, 'rb')
-        LOG.debug('Found package data for function %s', function)
+        LOG.debug('Found package data for function %s version %d', function,
+                  version)
 
         return f
 
diff --git a/qinling/tests/unit/api/controllers/v1/test_function_version.py b/qinling/tests/unit/api/controllers/v1/test_function_version.py
index da3f6ff4..b2e12c4d 100644
--- a/qinling/tests/unit/api/controllers/v1/test_function_version.py
+++ b/qinling/tests/unit/api/controllers/v1/test_function_version.py
@@ -108,3 +108,12 @@ class TestFunctionVersionController(base.APITest):
         actual = self._assert_single_item(resp.json['function_versions'],
                                           version_number=1)
         self.assertEqual("version 1", actual.get('description'))
+
+    def test_get(self):
+        db_api.increase_function_version(self.func_id, 0,
+                                         description="version 1")
+
+        resp = self.app.get('/v1/functions/%s/versions/1' % self.func_id)
+
+        self.assertEqual(200, resp.status_int)
+        self.assertEqual("version 1", resp.json.get('description'))
diff --git a/qinling/tests/unit/storage/test_file_system.py b/qinling/tests/unit/storage/test_file_system.py
index 97cd71c2..5e39ff82 100644
--- a/qinling/tests/unit/storage/test_file_system.py
+++ b/qinling/tests/unit/storage/test_file_system.py
@@ -150,6 +150,39 @@ class TestFileSystemStorage(base.BaseTest):
         )
         exists_mock.assert_called_once_with(package_path)
 
+    @mock.patch('qinling.storage.file_system.open')
+    @mock.patch('os.path.exists')
+    @mock.patch('os.listdir')
+    def test_retrieve_version(self, mock_list, mock_exist, mock_open):
+        function = "fake_function_id"
+        version = 1
+        md5 = "md5"
+        mock_list.return_value = ["%s_%s_%s.zip" % (function, version, md5)]
+        mock_exist.return_value = True
+
+        self.storage.retrieve(self.project_id, function, None,
+                              version=version)
+
+        version_zip = os.path.join(FAKE_STORAGE_PATH, self.project_id,
+                                   "%s_%s_%s.zip" % (function, version, md5))
+
+        mock_exist.assert_called_once_with(version_zip)
+
+    @mock.patch('os.listdir')
+    def test_retrieve_version_not_found(self, mock_list):
+        function = "fake_function_id"
+        version = 1
+        mock_list.return_value = [""]
+
+        self.assertRaises(
+            exc.StorageNotFoundException,
+            self.storage.retrieve,
+            function,
+            self.project_id,
+            None,
+            version=version
+        )
+
     @mock.patch('os.path.exists')
     @mock.patch('os.remove')
     def test_delete(self, remove_mock, exists_mock):