本文详细解释了8051单片机的看门狗原理，同时以STC89C52RC单片机为例书写了C语言代码，演示了看门狗的工作原理和机制。文中的代码稍加修改可以应用于AT89C5X单片机看门狗，STC12等系列的单周期指令单片机的看门狗。-This paper explain the watchdog of the 8051 single chip microcomputer principle, at the same time to STC89C52RC MCU as an example to write the C language code, demonstrates watchdog work principle and mechanism. The code can be used to modify a little bit AT89C5X SCM watchdog, STC12 series single cycle instruction SCM watchdog.