The variable frequency speed regulation system of EPS (electric power steering) surface PMSM (permanent magnetic synchronous motor) is made up of the PMSM、 the inverter、 the rotor position sensor and the control unit. The control of surface PMSM electric power steering system includes the torque control and the vector control. The torque control is the control target of the surface PMSM electric power steering system. And the vector control is the control of stator current vector of the surface PMSM. The control process of the surface PMSM electric power steering system is illustrated. The setting of the assist characteristic, the coordinate transformations and the PWM technologies of the control system of the surface PMSM electric power steering are analyzed.