Silane-grafted polypropylene(PP-g-Si)was prepared by means of reactive grafting process and used as the coupling agent for polypropylene/glass-fiber(PP/GF)composites.The effect of PP-g-Si on the interaction and mechanical properties of the composite was studied and compared with that of maleic anhydride grafted polypropylene(PP-g-MAH0.The results showed PP-g-Si had compatibilization effect on PP/GF and the effect was better than that of PP-g-MAH.