The invention provides a control method of a door motor, a control device of the door motor and a microwave oven with the control device. The control method comprises the following steps: receiving an instruction, and controlling the door motor to be started according to the instruction; recording the starting time t1 of the door motor; if the starting time t1 is within first preset time T1 and the state of a driving shaft detection switch of the door motor is not changed, judging that the door motor stalls or the driving shaft detection switch fails. According to the control method of the door motor, the condition that the door motor stalls or the driving shaft detection switch fails can be detected, and a product is protected during failure. In addition, after the condition that the door motor stalls or the driving shaft detection switch fails is detected, the door motor is continuously controlled to operate, so that a driving shaft can stop at a position where a door can be normally opened and closed, and the problem that the door cannot be closed due to the stopping position of the driving shaft when the driving shaft detection switch is subjected to detection failure is solved.