Abstract: The ultra high molecular weight polyethylene (UHMWPE) bearing material often suffers severe wear under low speed and heavy load condition. The tribological properties of UHMWPE bearing material can be greatly improved by adding self-lubricating filler. Atapulgite (ATP), as a modified filler, can enhance the mechanical properties of the material and improve its frictional properties, but agglomeration effect limits its dispersion in the matrix material. The surface modification of ATP can achieve uniform blending between ATP and the matrix. ATP modified by silane coupling agent KH570 was prepared by surface chemical coating modification method. The composite material was blended with UHMWPE and compared with pure UHMWPE. Under the condition of water lubrication, the variation of friction coefficient of composites under different loading and rotating speed conditions and the influence of material filling content on the wear performance of composites under low speed and heavy load conditions (v=0.55 m/s, F_z=55 N) were studied. Fourier transform infrared spectrometer, X-ray diffraction, differential scanning calorimetry and electronic universal material testing machine were used to characterize ATP modification effect, melt crystallization behavior and mechanical properties of composites. At the end of the experiment, the wear surface morphology of the composites and their duals was observed by surface profilometer and confocal laser microscope, and the wear mechanism was analyzed. The results showed that the silane coupling agent KH570 had a good effect on ATP modification, and the Shore hardness of the material was increased by filling ATP modification, and the tensile property of the material decreased with the increase of filling content. Compared to the pure UHMWP material, the friction coefficient of the composites was lower. An appropriate amount of ATP filling can improve the wear surface morphology and reduce the volume wear rate. In the experiment, the modified ATP content of 1% material had the best tribological properties, and its friction coefficient and volume wear rate at low speed and heavy load were reduced by 52.45% and 37.58%, respectively, compared to pure UHMWPE.