#include "reg51.h"sbit P1_7=P1^7;main(){EA=1;TMOD=0x01;ET0=1;TH0=0XF6;TL0=0X3C;TR0=1; }void timer0() interrupt 1 //using 0 //T0定时 定时50ms{ EA=0; TH0=0XF6; TL0=0X3C; P1_7=~P1_7; EA=1;}你先测试下, 没环境~