Abstract: Based on W-M fractal function, a three-dimensional transient sliding contact model of the contact friction pair of a mechanical seal was established. The mechanical interaction and thermal-mechanical coupling of friction between contact micro-convex bodies have been considered. Based on ABAQUS, a new computational model has been proposed for the first time using which the rotary motion of mechanical seal friction pair can be numerically simulated. The friction characteristics of a mechanical seal friction pair under dry operation were simulated and analyzed. The results show that the temperature distribution of the contact surface was uneven, the local temperature was very high and the maximum appeared in the center area of the contact micro-convex body. The temperature rose sharply in a very short time after sliding and the temperature of the contact node was rising with sliding, while the temperature rising rate slowed down. The temperature gradient of the rough body along the axial direction was large and the sub-surface area had a large thermal stress, which made thermal damage failure much easier. There was tensile stress in the local zone near the surface of the contact micro-convex body in axial direction, the sliding behavior enlarged the tensile stress zone inside the micro-convex body and the tensile stress also increased. The stress of the contact zone of the micro-convex body changed in the axial direction which subjected to continuous compression-tension-compression.