diff --git a/src/core/api/base.go b/src/core/api/base.go
index 90c4961dc..29874c7df 100644
--- a/src/core/api/base.go
+++ b/src/core/api/base.go
@@ -84,24 +84,20 @@ func (b *BaseController) RequireAuthenticated() bool {
 
 // HasProjectPermission returns true when the request has action permission on project subresource
 func (b *BaseController) HasProjectPermission(projectIDOrName interface{}, action rbac.Action, subresource ...rbac.Resource) (bool, error) {
-	projectID, projectName, err := utils.ParseProjectIDOrName(projectIDOrName)
+	_, _, err := utils.ParseProjectIDOrName(projectIDOrName)
 	if err != nil {
 		return false, err
 	}
 
-	if projectName != "" {
-		project, err := b.ProjectMgr.Get(projectName)
-		if err != nil {
-			return false, err
-		}
-		if project == nil {
-			return false, errors.NotFoundError(nil).WithMessage("project %s not found", projectName)
-		}
-
-		projectID = project.ProjectID
+	project, err := b.ProjectMgr.Get(projectIDOrName)
+	if err != nil {
+		return false, err
+	}
+	if project == nil {
+		return false, errors.NotFoundError(fmt.Errorf("project %v not found", projectIDOrName))
 	}
 
-	resource := rbac.NewProjectNamespace(projectID).Resource(subresource...)
+	resource := rbac.NewProjectNamespace(project.ProjectID).Resource(subresource...)
 	if !b.SecurityCtx.Can(action, resource) {
 		return false, nil
 	}
@@ -114,24 +110,42 @@ func (b *BaseController) HasProjectPermission(projectIDOrName interface{}, actio
 func (b *BaseController) RequireProjectAccess(projectIDOrName interface{}, action rbac.Action, subresource ...rbac.Resource) bool {
 	hasPermission, err := b.HasProjectPermission(projectIDOrName, action, subresource...)
 	if err != nil {
-		b.SendError(err)
-
+		if errors.IsNotFoundErr(err) {
+			b.handleProjectNotFound(projectIDOrName)
+		} else {
+			b.SendError(err)
+		}
 		return false
 	}
 
 	if !hasPermission {
-		if !b.SecurityCtx.IsAuthenticated() {
-			b.SendError(errors.UnauthorizedError(errors.New("Unauthorized")))
-		} else {
-			b.SendError(errors.New(errors.New(b.SecurityCtx.GetUsername())).WithCode(errors.ForbiddenCode))
-		}
-
+		b.SendPermissionError()
 		return false
 	}
 
 	return true
 }
 
+// This should be called when a project is not found, if the caller is a system admin it returns 404.
+// If it's regular user, it will render permission error
+func (b *BaseController) handleProjectNotFound(projectIDOrName interface{}) {
+	if b.SecurityCtx.IsSysAdmin() {
+		b.SendNotFoundError(fmt.Errorf("project %v not found", projectIDOrName))
+	} else {
+		b.SendPermissionError()
+	}
+}
+
+// SendPermissionError is a shortcut for sending different http error based on authentication status.
+func (b *BaseController) SendPermissionError() {
+	if !b.SecurityCtx.IsAuthenticated() {
+		b.SendUnAuthorizedError(errors.New("UnAuthorized"))
+	} else {
+		b.SendForbiddenError(errors.New(b.SecurityCtx.GetUsername()))
+	}
+
+}
+
 // WriteJSONData writes the JSON data to the client.
 func (b *BaseController) WriteJSONData(object interface{}) {
 	b.Data["json"] = object
diff --git a/src/core/api/metadata.go b/src/core/api/metadata.go
index a3d6fa68b..92084531e 100644
--- a/src/core/api/metadata.go
+++ b/src/core/api/metadata.go
@@ -69,7 +69,7 @@ func (m *MetadataAPI) Prepare() {
 	}
 
 	if project == nil {
-		m.SendNotFoundError(fmt.Errorf("project %d not found", id))
+		m.handleProjectNotFound(id)
 		return
 	}
 
diff --git a/src/core/api/metadata_test.go b/src/core/api/metadata_test.go
index 97dd59181..2fd6d823a 100644
--- a/src/core/api/metadata_test.go
+++ b/src/core/api/metadata_test.go
@@ -65,10 +65,10 @@ func TestValidateProjectMetadata(t *testing.T) {
 func TestMetaAPI(t *testing.T) {
 	client := newHarborAPI()
 
-	// non-exist project
+	// non-exist project, it should return 401 if user is not logged in.
 	code, _, err := client.PostMeta(*unknownUsr, int64(1000), nil)
 	require.Nil(t, err)
-	assert.Equal(t, http.StatusNotFound, code)
+	assert.Equal(t, http.StatusUnauthorized, code)
 
 	// non-login
 	code, _, err = client.PostMeta(*unknownUsr, int64(1), nil)
diff --git a/src/core/api/project.go b/src/core/api/project.go
index a73d3c28b..87c385404 100644
--- a/src/core/api/project.go
+++ b/src/core/api/project.go
@@ -79,7 +79,7 @@ func (p *ProjectAPI) Prepare() {
 		}
 
 		if project == nil {
-			p.SendNotFoundError(fmt.Errorf("project %d not found", id))
+			p.handleProjectNotFound(id)
 			return
 		}