Abstract: The reaction kinetics of n -butane selective oxidation to maleic anhydride over a domestic VPO catalyst was experimentally studied under a wide range of operation conditions.Space velocity was larger than 3000h ^-1 ,reaction temperatures were 350-446℃,feed concentrations of n -butane and oxygen were 0.5%- 3.2% and 5.5% - 26.5% respectively.A triangular reaction network was adopted to describe this complex reaction system.A set of intrinsic rate equations were identified by fitting the model of the laboratory reactor with experimental data and model parameters were estimated.Statistical test confirmed the study.