Abstract: A kind of microcapsule containing phase change material of paraffin wax was successfully prepared by process of in-situ polymerization using melamine resin as polymer shell material. Then it was added to the matrix of UHMWPE as the filler to prepare the UHMWPE-based composites. The hardness, phase composition and the tribological properties were investigated under both low-speed and high-speed test conditions at room temperature. The results show that the addition of microcapsules in the composites played a significant role in decreasing friction and reducing wear, and the optimum addition ratio of the microcapsules filler was 20% .The coefficient of friction of the modified composites decreased by 60% compared with that of pure UHMWPE under the low-speed test condition. While under the high-speed test condition, the wear resistance of the composites were improved obviously compared with that of the pure UHMWPE. The wear mechanism of the composites materials varied as different test conditions.