Surface of Ultra-high molecular weight polyethylene (UHMWPE) fiber were treated by chromic acid chemical etching, pyrrole chemical vapour phase deposition and the complex of these two methods, respectively. The change of surface properties and structure of fibers were discussed by Fiour Transform Insfrared Spectroscope (FTIR), Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscope (SEM). The results show that some new oxygenous groups could he found on surface of UHMWPE fiber after chromic acid chemical etching, which enhanced intermolecular interaction with polypyrrole. The adhesion of the fibet and resin matrix increased after pyrrole chemical vapour deposition. When chromic acid etching combined with pyrrole clinical vapor deposition, the treated fiber not only has the same properties as original fiber but also outstanding adhesion to epoxy resin matrix, and its composites have better mechanic properties (shear strength), resulting from intermolecular interaction between treated fiber and polypyrrole.