diff --git a/src/include/data.h b/src/include/data.h
index 991b05d..f5884c1 100644
--- a/src/include/data.h
+++ b/src/include/data.h
@@ -41,5 +41,6 @@ struct CoreTrainData {
 
 struct SeatsData {
   uint32_t seat[99];
+  uint32_t max_seats;
 };
 #endif
\ No newline at end of file
diff --git a/src/train_system.cpp b/src/train_system.cpp
index 75b4099..cb03b1a 100644
--- a/src/train_system.cpp
+++ b/src/train_system.cpp
@@ -171,6 +171,7 @@ std::string TicketSystemEngine::AddTrain(const std::string &command) {
   for (int i = 0; i < core_train_data.stationNum - 1; i++) {
     seats_data.seat[i] = core_train_data.seatNum;
   }
+  seats_data.max_seats = core_train_data.seatNum;
   int day_count = core_train_data.saleDate_end - core_train_data.saleDate_beg + 1;
   for (int i = 0; i < day_count; i++) {
     seats_data_storage.Put(std::make_pair(train_id_hash, i), seats_data);
diff --git a/src/transaction_system.cpp b/src/transaction_system.cpp
index 2aa2921..92c2912 100644
--- a/src/transaction_system.cpp
+++ b/src/transaction_system.cpp
@@ -251,7 +251,7 @@ std::string TicketSystemEngine::BuyTicket(const std::string &command) {
     available_seats = std::min(available_seats, (int)seats_data.seat[j]);
   }
   if (ticket_num > available_seats) {
-    if (accept_queue == "false") {
+    if (accept_queue == "false" || ticket_num > seats_data.max_seats) {
       LOG->debug("no enough seats");
       response_stream << "[" << command_id << "] -1";
       return response_stream.str();