The effects of Bi on the catalytic performance of selective oxidation of isobutane to methacrolein over MoVO/AlPO4 catalyst were investigated by XRD,FT-Raman,XPS,UV-vis DRS techniques.The results show that the addition of Bi component into the MoVO/AlPO4 catalyst obviously improves the catalytic performance,and the selectivity to methacrolein can increase from 14.2％ to 45.1％ with the increase of Bi/V molar ratio from 0 to 1.Combining the characterization results with the reaction evaluation,it is concluded that the catalytic activities of the MoV0.3Bix/AlPO4 catalysts are related to the crystalline phase composition and the dispersion of molybdenum and vanadium oxides species in general,and also to the V5+/V4+ molar ratio on the surface in particular.