The co-gasification power generation technology of coal and biomass is a promising technique that can effectively reduce the environmental pollution caused by fossil fuels. This study used Aspen Plus software to simulate a coal and biomass co-gasification chemical looping combined cycle power generation system, using Zhundong coal and reed bamboo as co-gasification feedstocks, to investigate the impact of the biomass blending ratio on the co-gasification power generation system. The results show that, under the condition of maintaining a total input chemical energy of 150 MW, as the mass blending ratio of reed bamboo increases from 0 to 100%, the system's net power generation efficiency decreases from 42.00% to 31.01%, and the exergy loss ratio of the chemical looping subsystem increases from 51.44% to 67.80%. Moreover, the mass blending ratio of reed bamboo is positively correlated with the levelized cost of electricity of the power generation system, but negatively correlated with the net power generation efficiency. Finally, as the carbon trading price gradually increases, the advantages of biomass power generation become more pronounced.