Abstract: This paper studies the co -gasification reaction of biomass char and coals by non -isothermal thermo gravimetric analysis. The change of the characteristic temperature of co-gasification reaction was investigated, while Doyle and Coats-Redfern approximate functions could be used to simulate kinetics parameters of the reaction. The data calculated by using Doyle method hold a higher value of R² than the Coats -Redfern method. The Doyle method is more reasonable. In Doyle method, the apparent activation energy of the biomass char used is about 134.97 kJ/mol,while the bituminite is 197.85 kJ/mol and the anthracite is 171.36 kJ/mol. As the weight rate of biomass char added in coals become larger, the apparent activation energy become smaller. It was concluded that biomass char can make a promote role in coals' gasification process through lowing the final reaction temperature and the apparent activation energy.