The invention discloses a motor controller based on an analog-to-digital conversion overcurrent protective circuit, and belongs to the technology of the electronic circuit. A voltage sampling module samples the motor working current, a timer in an overcurrent protective module respectively outputs the first enable signal ena and a second enable signal enb at a first time node and a second time node, thereby controlling an analog-to-digital converter (ADC) to convert the output voltage VC1 of the voltage sampling module into a corresponding digital signal, and the digital signal is respectively stored in a first register and a second register, wherein the first time node is the power-on moment, and the second time node is a time node in the power-on process; a subtractor subtracts an output signal of the second register by using the output signal of the first register under the control of the second enable signal enb, the obtained output signal of the subtractor is used for recognizing whetehr the motor is locked-rotor after being synthesized through a logic circuit and then is input into a drive module; and the drive module controls the on and off of the motor by controlling an electronic relay module.