Self -recovery overvoltage/undervoltage protector circuit. It has solved the user can't detect the problem whether protector still had the undervoltage protection function. It includes power supply circuit, processing circuit, drive circuit and sampling circuit, sampling circuit is the A point with processing circuit's tie point, sampling circuit is used for detecting mains voltage to with sample voltage signal transmission to processing circuit, the last control switch who is used for changing A point voltage that is equipped with of sampling circuit, processing circuit is used for handling the judgement and driving drive circuit the sample voltage signal, drive circuit includes relay and pilot lamp, and drive circuit is used for the drive signal according to processing circuit, accomplishes the drive of relay and pilot lamp. The utility model discloses a self -recovery overvoltage/undervoltage protector circuit has the function of testing the undervoltage protection function and whether becoming invalid, has improved user's use and has experienced, and the range of application is wider.