diff --git a/paddle/utils/Flags.cpp b/paddle/utils/Flags.cpp
index 59d6cbdc513660b87cb013d8aa92c5c8f9289ecb..e8f31bc811ac30d83e8203b784ee1f93a8d35d90 100644
--- a/paddle/utils/Flags.cpp
+++ b/paddle/utils/Flags.cpp
@@ -33,12 +33,15 @@ DEFINE_int32(port, 20134, "Listening port for pserver");
 DEFINE_int32(data_server_port, 21134, "Listening port for dserver");
 DEFINE_int32(ports_num,
              1,
-             "The ports number for parameter send,"
-             " increment based on default port number");
+             "Number of ports for sending dense parameter,"
+             " following ports on parameter server will be visited"
+             " for sending dense parameter: [port, port+ports_num-1]");
 DEFINE_int32(ports_num_for_sparse,
              0,
-             "The ports number for parameter send,"
-             " increment based on default (port + ports_num)");
+             "Number of ports for sending sparse parameter,"
+             " following ports on parameter server will be visited"
+             " for sending sparse parameter:"
+             " [port+ports_num, port+ports_num+ports_num_for_sparse-1]");
 DEFINE_string(nics, "xgbe0,xgbe1", "network device name for pservers");
 DEFINE_string(rdma_tcp, "tcp", "use rdma or tcp rdma transport protocol");
 DEFINE_int32(trainer_id,
diff --git a/proto/ParameterServerConfig.proto b/proto/ParameterServerConfig.proto
index 3068bba8b10d89b432b41076dc6eb3ebc40b3883..404f9613792653dda72eeb98f022851adedbfbfd 100644
--- a/proto/ParameterServerConfig.proto
+++ b/proto/ParameterServerConfig.proto
@@ -27,11 +27,14 @@ message ParameterClientConfig {
  * Configuration structure for ParameterServer2.
  */
 message ParameterServerConfig {
-  // The ports number for parameter send,
-  // increment based on default port number
+  // Number of ports for sending dense parameter,
+  // following ports on parameter server will be visited
+  // for sending dense parameter: [port, port+ports_num-1]
   required int32 ports_num = 1 [default = 1];
-  // The ports number for parameter send,
-  // increment based on default (port + ports_num
+  // Number of ports for sending sparse parameter,
+  // following ports on parameter server will be visited
+  // for sending sparse parameter:
+  // [port+ports_num, port+ports_num+ports_num_for_sparse-1]
   required int32 ports_num_for_sparse = 2 [default = 0];
   // network device name for pservers
   required string nics = 3 [default = "xgbe0,xgbe1"];