I set a task:
xTaskCreate( vTimeTask, (signed char *) "TIME1", configMINIMAL_STACK_SIZE, NULL, mainTIME_TASK_PRIORITY, &T1 );

In this task, I sending out string by uart:
int i;
Usart_SendString(USART3,"first\r\n");
delay(300);
Usart_SendString(USART3,"second\r\n");
delay(300);

i=Starts();

and in this Starts() method, I put only oneline:
Usart_SendString(USART3,"System starts.....\r\n"); //this line has problem.

Strainge thing is that there is only few chars show on uart: "Syste"
However, if I move Usart_SendString(USART3,"System starts.....\r\n"); out of method Starts(), it runs well.

And same codes runs well without FREERTOS platform.

how to fix this?

sorry, my code has error. it is fixed now.
no need reply to this question.