The output torque of a doubly salient electro-magnetic machine (DSEM) is related to the selection of the advance angle. Due to the nonlinear characteristics of DSEM, multiple finite element simulations and experiments are usually used to obtain the appropriate advance angle, and it needs to be reselected when the operating conditions change. To simplify the selection of the advance angle, an advance angle self-optimizing control of the DSEM drive system is proposed in this paper. Firstly, the relationship between the DSEM armature current enveloping area and the output torque is analyzed. With this for basis, the output torque estimation model is established. Then, the advance angle self-optimization control method is proposed. The advance angle of the DSEM drive system is perturbed by a fixed step. Based on the torque estimation model, by comparing the output torque of DSEM under different advance angles, the maximum output torque corresponding advance angle of the DSEM is automatically optimized. Finally, the effectiveness and feasibility of the proposed method are verified by field-circuit co-simulation and experiment on 12/8 DSEM.