Abstract: The kinetics of oxidation of methanol to formaldehyde on Mo-Bi-Ce/SiO_2 catalyst has been investigated in an external recirculation gradientless reactor. The kinetic data can be described by a two-stage redox model. The parameters of the kinetic equation were estimated by the linear least square method. The m-order with respect to methanol and n-order with respect to oxygen depended on the reaction temperature and m+n=1 (the sum of m and n is close to 1). The change of reaction order was interpreted by the kinetics of redox mechanism. XPS results which come from different treated catalysts verify the redox mechanism mentioned above.