SnSO4 is an important promoter of catalyst for preparing naphthalene quinone with oxidation of naphthalene by air.Its thermal decomposition kinetics in N2was studied with NETZSCH-STA409PC thermal analyzer.SnSO4 thermal decomposition was an endothermic reaction and mainly occurred at 450-550℃.The total mass loss was 29.36%,so the reaction products were SnO2 and SO2.Kinetic function was obtained and kinetic parameters were calculated with linear regression provided by NETZSCH Instruments Co.Ltd.The correlation coefficient was 0.9997.The results showed that SnSO4 decomposition was a self-catalysis reaction and the catalyst was its reaction product.The kinetic function predicted that SnSO4 decomposition was 20% at 450℃ for 120 min and 100% at 480℃ for 106 min,and the process of catalyst preparation can be optimized.