A numerical simulation model of reciprocating seals was developed base on mixed lubrication theory.The macroscopic solid mechanical deformation of seals,the microrough peak contact in the contact zone and the oil film thickness distribution in the sealing system were considered in this model,and the key performance parameters such as friction force and leakage of reciprocating seals can be obtained by analysis.Bench tests were carried out with the commonly used Step seal in reciprocating seal as the research object,the friction and leakage of the Step seal were measured.The experimental and simulation results show that the instantaneous friction force of the Step seal is increased with the increase of the medium pressure, and the leakage of reverse Step seal is increased with the accumulation of reciprocating stroke.The experimental results are basically consistent with the simulation results,which verifies the validity of the simulation model.