Abstract: Through removing polymer physisorbed on the glass fiber surface with solvent extraction to minimize the signal of the polymer in IR and XPS analysis,the interaction was studied by IR and XPS between maleic anhydride grafted polypropylene(MA-g-PP)and an amino silane coupling agent-γ-aminopropyltrimethoxy silane(APS).It is found that the absorption bands of polypropylene still exits in IR spectra of the glass fiber after 72h dimethyl benzene extraction and a new state of N1s at 401.9eV appears in the XPS,which shows that the MA-g-PP and APS have reacted chemically and the reaction product with amido is formed.Although open chain APS and cyclic APS with an internal hydrogen bond coexist on the APS treated glass fiber surface,it is discovered that APS which reacts chemically with MA-g-PP is mainly open chain APS by the quantitative analysis of XPS for N1s in different chemical state.