The invention relates to the device field of controlling the synchronous motor, to be specific, relates to a tracking method of a rotor position of a salient pole permanent magnet synchronous motor in a motion state. The tracking method is characterized in that a, comparison is carried out; b, input of a PWM inverter is carried out; c, current i alfa beta of an alfa beta axis can be acquired; d, a current signal i alfa beta comprising the rotor position information can be acquired; e, whether the polarity of the estimated rotor position is identical to the polarity of the actual position can be determined, when the polarities are opposite, the compensation is required; f, after the current i afla beta is transmitted to the phase-locked loop, the estimated rotor angular speed omega r and the estimated rotor position theta r can be acquired by combining with the polarity determining module. The tracking method has advantages of high accuracy, strong applicability, safety, and reliability.