The parameters identification method of traditional motor often used fixed pulse width modulation (PWM) wave duty cycle, which led to uncontrollable identification current, and the accuracy of identification and was directly affected by the size of identified current. A new parameters offline identification method was proposed, which was based on the principle of constant current identification. It solved the problem of inappropriate identification current of motor by detecting the phase current of motor and controlling the fluctuation of identification current near the given value. The model of the flywheel diode and IGBT voltage was designed, which required that both daxis and qaxis inductance identification should be carried out at 270° instead of 0°, thus it could improve the identification accuracy. Finally, the method was applied to the frequency conversion refrigerator, and the experimental results were compared with the original data. This method could effectively solve problems such as inaccurate identification of the d,qaxis inductance and long identification time of the refrigerator motor with back pressure. The experimental results showed that the new method was feasible and effective.