Commutation deflection angle adjustment is a feasible way to improve PMDC performance, but its research is relatively simple. Combined with the convenient characteristics of RMxprt simulation PMDC, this paper carries out the simulation research on the impact of commutation deflection angle adjustment on PMDC performance. Firstly, the PMDC model is established in rmxprt through the example parameters of the research object, and then the commutation deflection angle parameters are modified based on the model to obtain the rated speed, energy conversion efficiency, working current and cogging torque under different deflection angles. The influence law of commutation deflection angle on PMDC performance is summarized, and the influence of commutation deflection angle on speed and working current is verified through test experiments. The simulation and test results show that the commutation deflection angle can adjust PMDC speed and working current, improve PMDC energy conversion efficiency and reduce PMDC cogging torque. Compared with other optimization methods, the commutation deflection angle adjustment method has the advantages of flexible application and high cost performance.