A novel direct torque control based on terminal sliding mode controller for doubly salient electro-magnetic machine was proposed in this paper. The mathematical model of the motor has been constructed and generation principle of torque ripple was analyzed. Based on analysis of torque ripple, phase current waveforms had been optimized to reduce the electro-magnetic torque ripple by using direct torque control strategy. Meanwhile, torque observer was built to calculate output torque of the machine in real time and terminal sliding mode controller was applied in speed regulating loop to improve dynamic response. Moreover, the stability characteristic of terminal sliding mode controller was proved by Lyapunov function. Finally, a field-circuit co-simulation model was built and some simulation results verify the feasibility of control strategy and theory analysis.