Abstract: In this parper, a series of P-Mo based multiple component catalysts, P1.33-dMo12VaCubSbcAsdK1.5Ox／SiC（0.0≤a，b，c，d≤0.50）, were prepared by co-precipitation method. The structure and properties of the catalysts were investigated by means of XRD，FTIR, DSC and ESR. The results of XRD and FTIR show that the catalyst is P-Mo heteropoly compound that possess Keggin heteropolyanion structure. The study of DSC and ESR indicate that the catalyst have good stability. The effect of content of catalyst on catalytic activity for isobutane oxidation was evaluated. It was found that the addition of V, Cu, Sb, As with appropriate amount can improve the selectivity of methacrylic acid and yield of MAA+MAL to some extent. For catalyst P1.13Mo12V0.25Cu0.25Sb0.25As0.2K1.5Ox／SiC, the conversion of isobutane is 10.7％, the yield of MAA+MAL is about 6.8％ under the reaction condition: 360 ℃, atmospheric pressure, feed composition: isobutane∶air=1∶2(mol), and GHSV=3 600 h－1.