In view of the poor speed tracking accuracy of permanent magnet synchronous motor (PMSM) under low speed operation, inputoutput precise feedback linearization control was used to explore highprecision PMSM lowspeed operation characteristics. In order to obtain better precise control performance, the decoupling model of PMSM inputoutput precision feedback linearization was obtained by differential homeomorphic transformation and feedback linearization theory. Then, based on this decoupling model, precise control of PMSM at low speed was achieved. Simulation and experimental results applied to PMSM showed that the proposed approach could quickly track load torque and command speed, and the system had advantages of small overshoot, small static error, high robustness and high control accuracy.