diff --git a/proto/common.proto b/proto/common.proto
index c768801..6c9ea8f 100644
--- a/proto/common.proto
+++ b/proto/common.proto
@@ -8,6 +8,8 @@ option java_package = "io.milvus.grpc";
 option java_outer_classname = "CommonProto";
 option java_generate_equals_and_hash = true;
 
+option csharp_namespace = "IO.Milvus.Grpc";
+
 import "google/protobuf/descriptor.proto";
 
 enum ErrorCode {
diff --git a/proto/milvus.proto b/proto/milvus.proto
index 4b81e69..06ff231 100644
--- a/proto/milvus.proto
+++ b/proto/milvus.proto
@@ -8,6 +8,8 @@ option java_package = "io.milvus.grpc";
 option java_outer_classname = "MilvusProto";
 option java_generate_equals_and_hash = true;
 
+option csharp_namespace = "IO.Milvus.Grpc";
+
 import "common.proto";
 import "schema.proto";
 import "google/protobuf/descriptor.proto";
diff --git a/proto/schema.proto b/proto/schema.proto
index 3b8c066..a2682bb 100644
--- a/proto/schema.proto
+++ b/proto/schema.proto
@@ -8,6 +8,8 @@ option java_package = "io.milvus.grpc";
 option java_outer_classname = "SchemaProto";
 option java_generate_equals_and_hash = true;
 
+option csharp_namespace = "IO.Milvus.Grpc";
+
 import "common.proto";
 
 /**