Abstract: In applications, some system parameters are unknown or uncertain. In order to solve the problem of synchronous control and parameter identification of permanent magnet synchronous motor with unknown parameters, a dynamic model of a uniform air-gap permanent magnet synchronous motor drive-response system with two unknown parameters is established. Based on Lyapunov function method and inequality technique, a simple and novel adaptive controller and unknown parameter adaptive law are designed and detailed theoretical derivation is carried out. Theoretical analysis shows that the permanent magnet synchronous motor drive-response system can realize the synchronization and can effectively identify the unknown parameters. Finally, the simulation results verify the correctness of the theoretical derivation and the robustness of the system to unknown parameters.