Aiming at the problem of realtime perturbation of the motor parameters affected by the operating conditions during the operation of the permanent magnet synchronous motor (PMSM), a multiparameter parallel online identification algorithm for PMSM based on rank deficient steady equation was proposed. The coefficient matrix of the steady state equation of PMSM was analyzed, and the steady state equation of PMSM was the rank deficient equation with the rank number of two and three unknown parameters was pointed out. Based on the theory of Lyapunov stability and Popov super stability theory, the PMSM model reference adaptive multiparameter parallel identifiers were designed. By designing reasonable adaptive law, the reference adaptive system is gradually stabilized, and the motor stator resistance, inductance and rotor flux were identified correspondly. The experimental results verified the validity and practicability of the proposed algorithm.