Abstract: In order to understand the combustion kinetic characteristics of the molded particles compressed by different cotton stalk powder size,the thermos-gravimetric analysis of powder with different size is carried out firstly,and then the powder with different sizes is compressed into particles with same weight.After that,the weight loss experiments during the molded particle combustion are conducted.At last,the kinetic analysis is carried out by using the double logarithmic method of isothermal analysis.The results indicate that more ash is found in the big size powder.The ash may build the skeleton under lower temperature combustion,which strengthens the diffusion of volatiles and oxygen so that the combustion velocity is accelerated.During the process of compressing particles,the smaller the powder size of raw cotton stalks,the tighter powder united.The mass loss rate of combustion under the same condition is reduced significantly.The apparent activation energy is reduced form 77.71 kJ/mol to 69.44 kJ/mol.The process of particle combustion may be divided into two stages.In first stage,all of the water and volatiles are volatilized,In second stage,the residual char burned.The combustion temperature significantly increases the precipitation rate of water and volatile components.