A permanent magnet synchronous motor (PMSM) with NdFeB and ferrite hybrid permanent magnets for hybrid electric vehicle integrated starter generator (ISG) was designed. The influence of the structure parameters of the two permanent magnets on the magnetic circuit of the motor was analyzed, and the constraints of the parallel magnetic circuit of NdFeB and ferrite were deduced. With the irreversible demagnetization of ferrite and the basic performance of the motor as the optimization objective, the structure parameters of NdFeB and ferrite were determined by fieldcircuit combining method. The NdFeB PMSM was compared and analyzed in terms of motor performance and permanent magnet cost. The results showed that the ISG hybrid permanent magnet motor proposed could effectively reduce the cost of permanent magnet materials and the risk of ferrite demagnetization, and the performance of the motor met the design requirements.