The d-q axis current of the PMSM under the vector control cannot be dynamically decoupled, which brings difficulty in adapting to the dynamic changes of the motor parameters. The stability of the motor control system is affected. To address this issue, this article proposes a deviation decoupling control method of the PMSM based on the parameter identification (PI-DDC). First, taking the coupling coefficient of the d-q axis current controller as zero, and the transfer function of the deviation decoupling could be obtained under this condition. Then, the dynamic changes of the motor parameters that affect the decoupling effect of the deviation decoupling can be considered, such as the resistance, inductance and permanent magnet flux. The recursive least square method with the forgetting factor is introduced to online identify the motor parameters, which are further used to correct the corresponding values in the deviation decoupling control model real time and the current decoupling of d-q axis can be realized. A case study has been carried out on a PMSM. The simulation and experimental results under different working conditions validate the better control accuracy and dynamic performance of the proposed PI-DDC method comparing with the traditional deviation decoupling control method. The response time, overshoot and fluctuation amplitude of the d-q axis current are decreased about 50% , 60% and 70% , and 30% and 37% respectively.