Abstract: To enhance the interfacial adhesion between silica fibers(SF) and the polyarylacetylene matrix（PAA）, the modification phenolic resin was used as the surface treatment agent for SF. The influence of treatment technology on the silica fibers reinforced polyarylacetylene composites (SF/PAA) mechanical property and dielectric property was investigated by properties testing. The composition and functional group of the silica fiber surface were examined by X---ray photoelectron spectroscopy (XPS). The fracture surface of the composites was observed by scanning electron microscopy (SEM). The results of the properties testing indicate that mechanical property and dielectric property of the composites treated by modification phenolic resin are increased greatly. From XPS analysis, it can be seen that the interface of silica fiber has been grafted with the modification phenolic resin. Compared the SEM photographs of fracture surfaces of the composites, it shows that the interfacial adhesion of the composites treated by the modification phenolic resin is improved greatly.