Abstract: Thermal degradation behavior and kinetics of cotton fiber were investigated by thermogravimetric analysis(TG) and differential thermogravimetric(DTG) at different heating rates under highly purity N2.The thermal degradation kinetic parameters of cotton fiber were determined using Flynn-Wall-Ozawa and Coast-Redfern methods,which established its kinetic equation and isothermal kinetic model of the major degradation process through selecting different thermal degradation mechanisms.The model obtained could describe the decomposition behaviour of cotton fiber.The results indicated that the main thermal degradation process probably generated chemical reaction from amorphous region to crystalline field.The major kinetic mechanism model was described as a diffusion-controlled process via one-dimensional diffusion.The thermal degradation velocity of cotton fiber was mainly depended on temperature and degree of decomposition,which increased with the increase of temperature and decrease of degree of decomposition.