Abstract: As a polymer material slides against the metal counterpart, the interface transfer is the formation of the transfer film on the surface of the metal counterpart. The presence of the transfer film effectively reduces the wear of the polymer material. The process of interface transfer of a PTFE/45 steel tribo-pair was simulated based on a discrete element method. The Particle Flow Code in 2 Dimensions (PFC2D) was employed to simulate the process. The simulation results show the formation of transfer particle layer on the worn surface of 45 steel. At initial stage, the number of the transfered particles increased gradually. After that, the number of the particles tended to be a constant value and a the dynamic equilibrium with the formation and integrity of the transferred particle layer was obtained. And the rate of the number of wear particles against time decreased significantly and reached at a stable value.