In order to study the influence of surface structure of the combination seal on the sealing performance,single groove and double groove were machined on the surface of square ring.ABAQUS was used to simulate and analyze the stress and contact pressure distribution of rotary combination seal rings with different surface structures after interference installation and fluid loading.The influence of the size change of the oil groove width on the combined sealing performance was studied.The simulation results show that the maximum von Mises stress of the O-ring is decreased after interference installation and fluid loading,while the maximum von Mises stress of the grooved sealing ring is increased,and the stress increase is larger after interference installation.The contact surface of the grooved sealing ring is divided into multiple sections by the oil groove,the contact pressure curves of each section are similar in shape,but the contact pressure is increased in different degrees.The maximum von Mises stress value of the square ring is increased as the oil groove width increases under interference installation state,while the maximum von Mises stress value is decreased to varying degrees under fluid loading state.The addition of oil grooves on the surface of the square ring is conducive to the formation of multiple dynamic pressure lubrication areas on the dynamic sealing surface,which has a certain effect on enhancing sealing performance and improving lubrication conditions.However,adding oil grooves will increase the stress of the square ring and the risk of fatigue damage.