In order to reduce the thermal expansion coefficient of the polymer used as friction pair,the ultra-high molecular weight polyethylene (UHMWPE) was modified with multi-walled carbon nanotubes (MWCNTs),and the MWCNTs/UHMWPE composite material was prepared by the hot pressing method.The percolation threshold was calculated by measuring the conductivity to characterize the dispersion.The thermal expansion rate of the composite was tested with a thermal dilatometer (DIL),and the tribological properties of the composites with different MWCNTs contents were tested in a dry friction environment.The results show that the composite material obtained by the method of alcohol ultrasonic dispersion and regrind has good dispersibility.MWCNTs can effectively improve the thermal expansion properties of UHMWPE without reducing the tribological properties of UHMWPE.The composite material modified by mass fraction of 0.8% MWCNTs shows excellent friction reducing and anti-wear properties.The thermal expansion coefficient shows a correlation with the tribological properties,the lower the thermal expansion coefficient,the better the wear resistance.