Abstract: It is a feasible way for large-scale use of biomass by co-gasification of its char with coal. And the alkali metal salts contained in the biomass can act as the catalyst during gasification. Several co-gasification experiments between coal and straw char were carried out by thermal gravimetric analysis in non-isothermal mode under CO₂ atmosphere at the heating rate 20℃/min and the final temperature 1 200℃. The results show that there is no synergy between the two fuels during the pyrolysis stage, however, an obvious synergy effect is found in gasification stage when the temperature is greater than 800℃. Compared with the results calculated without considering the synergy, the coal gasification reaction is promoted when some straw chars are added. As a result, the final gasification temperature is lowered by 26℃ and the maximum weight loss rate is increased by 22%. The synergy is mainly due to the catalysis of the alkali metal in rice straw. The kinetic analysis shows that the gasification activation energy of the blend fuel is lower than that of coal alone.