Friction and wear behaviors of UHMWPE fabric composites in seawater and machine oil mediums were evaluated in a pin on disc friction and wear tester.The worn surface and transfer film of UHMWPE fabric composites examined with scanning electron microscope (SEM).The results indicate that,seawater and machine oil can improve the antifriction property due to the formation of the soft film and lubricative film respectively on the counterpart surface.As the infiltration of the water molecule and oil molecule reduces the bonding strength between the fiber and resin,the antiwear property of composites is decreased.