Abstract: Based on the numerical simulation of the rough surfaces and Reynolds equation,the calculation model for planar thrust sliding bearing with considering microcosmic topography was established.By use of a specific example,the changes of the maximum oil film pressure,bearing capacity and minimum oil film thickness of the thrust bearing during rotating were numerically calculated by using Matlab programming.The results show that the lubricating performance of planar thrust sliding bearing is relative with its microscopic morphology.The influences of rotation speed and surface roughness on the lubrication performance of thrust sliding bearing were studied in detail.The curves of relations between rotation speed,bearing capacity and friction torque under the condition of full lubrication film were obtained,and these correlation curves were analyzed.