An electronic device includes a motor, a sensing device and a controller. The motor provides a motive power to the load. The sensing device measures a plurality of motion parameters of the motor. The controller calculates a real system parameter between the motor and the load according to the motion command and the plurality of motion parameters. According to the motion command and the plurality of motion parameters, the controller acquires a real value of a rotation speed of the motor. Moreover, controller establishes a system model according to the motion command and the real system parameter so as to acquire an estimated value of the rotation speed of the motor. If the first mean square error is not smaller than the first target value, the controller performs a particle swarm optimization algorithm to change the estimated value of the rotation speed of the motor.