Abstract: Thermal and thermo-oxidative degradation of chitin with ammonium nitrate,ammonium sulfate and concentrated sulfuric acid were studied.Ammonium nitrate accelerated both thermal degradation and thermo-oxidative degradation,and ammonium sulfate and concentrated sulfuric acid promoted the thermo-oxidative degradation,but delayed thermal degradation.All of these three additives changed the condensed phase products of chitin after isothermal treatment.