The finite element simulation model of the sealing structure of electrohydraulic servo swing motor was established to study the performance of sealing structure.Three kinds of sealing structures, the rectangular sealing structure, the trapezoidal sealing structure, the star sealing structure were investigated by simulation method under the conditions of the same pre-compression and different medium pressure, and the sealing effect of three kinds of sealing structures were compared according to the results of simulation analysis.The results show that the star seal structure has four sealing lips on the cross-section and can avoid the distortion of seal structure in the groove, its sealing effectiveness is better than the rectangular seal structure and it is more suitable for high-power hydraulic sealing system.For the trapezoidal seal structure has a steeper pressure gradient near the fluid end and a moderate pressure gradient at one end, the leakage is reduced, and good sealing effect is achieved compared with the star and rectangular seal structure.