Abstract: In order to study the mixed combustion characteristics of biomass, the numerical simulation and experimental study were carried out on a boiler with a cylindrical combustion chamber. The temperature distributions of corn stalk, cotton stalk, sawdust and rice straw on the central section of combustor were simulated by Fluent software. Based on the simulation results, the co-combustion of corn stalk with the highest cross-section temperature and rice straw with the lowest cross-section temperature in the center of the combustor was further simulated and experimentally studied, and thus the effects of different mass mixing ratio, primary air velocity and primary air temperature on the mixed combustion of biomass were studied. The results show that the order of the highest temperature on the central section of the combustor is: corn stalk ＞ cotton stalk ＞ sawdust ＞ rice straw. The highest temperature of corn straw was 100 K higher than that of the other three kinds of biomass. The optimum mixing ratio of corn straw and rice straw was 7:3. The optimum primary air velocity and temperature were 48 m/s and 1 300 K. Under the optimum mixing parameters, the combustion characteristics of biomass single combustion were improved and the problem of low calorific value of biomass single combustion was solved effectively. The combustion characteristics of corn straw and rice straw under the optimum mixing parameters were studied by the mixed combustion experiment, and the good agreement between the simulated and experimental values was verified.