A motor controller according to the present disclosure obtains the rotational speed determination signal of the motor through the microprocessor and the rotational speed collector, and then outputs the first control signal by the first logic operation circuit based on the speed of the motor, to make the driving circuit control the main circuit to work normally or enter the safety state. In addition, the motor controller generates and outputs the second shutoff signal by the monitoring chip based on the working state or the output instruction of the microprocessor, and then outputs the second control signal by the second logic operation circuit based on the second shutoff signal and whether the DC bus voltage of the main circuit is in an overvoltage state, to make the driving circuit control the main circuit to stop receiving the first control signal and enter the safety state.