The invention discloses a recognition device and method for the operation state of a motor. Without affecting the normal operation of the motor, the operation state of the motor is determined by judging the voltage and current phase characteristic comparison signal of the single phase of the motor. Voltage and current signals of the motor are accurately detected and processed to acquire the operation state signal of the motor. According to the invention, the device and method are applicable to various asynchronous motors, have the advantages of simple structure, strong anti-interference and fast response, have an important significance for the control of a later system, and can be applied to various occasions with the requirements of stable grid voltage and energy recovery in power systems, industrial and mining enterprises, transportation and the like.