With the development of AC (alternating current )technique, larger power PMSM ( permanent m- agnet synchronous motor ) has been applied in the marine electric propulsion systems. In this paper the imple- mentation of the DTC (direct torque control) systems for a variable-speed 4088kW PMSM in ship electric propulsion systems has been studied. A novel control method using SVPWM (space vector pulse width mo- dulation) was proposed and a SVPWM module was designed. Then a DTC – SVPWM simulation model of PMSM with the load of propeller was found. The simulation results shows that the variable frequency speed regulation system have good response performance in the process of the motor start or speedup and through comparing the simulation results with the experiment data of the PMSM, the validity of the model is verified.