In order to avoid the magnetic flux leakage of winding cylinder of DSMRD, the magnetic field simulation models under different winding cylinder materials were built up to investigate the relationships between the magnetic flux leakage and three winding cylinders made by different kinds of materials. The simulation results show that winding cylinder made by No. 10 steel material has stronger ability to reduce flux leakage than the winding cylinder made by aluminum and stainless steel materials, and the winding cylinders made by aluminum and stainless steel materials have nearly same magnetic field intensity and induced voltage. The simulation results can provide some guidance to optimize magnetic field by finding a suitable winding cylinder material.