The utility model discloses a frequency converter input overvoltage protection device and relates to a voltage protection device at the input end of a frequency converter. The device comprises a voltage detection module, a control module and a shutdown device, wherein the voltage detection module is used for detecting the voltage of each of the first three phases of power cords of a frequency converter, the control module is used for judging whether switching off is performed or not according to detection signals of the voltage detection module, and the shutdown starts to work according to the commands of the control module; the voltage detection module is a voltage transformer, and the output detection signals of the voltage detection module are transmitted to the control module; the shutdown device is an AC (alternating current) contactor, and the coil of the AC contactor is connected with the control module; and the control module is a PLC (programmable logic controller). The device provided by the utility model is suitable for detection protection in case of overvoltage at a power supply input end or overvoltage control to the switching function of an external circuit, and can be independently used at the power supply input terminal for achieving the required protecting function. Therefore, the device has the advantages of simple circuit, lower cost and higher reliability.