Biomass chemical looping gasification (BCLG) is a promising biomass utilization and carbon capture technology, while Organic Rankine Cycle (ORC) is an energy conversion technology that can achieve a higher energy grade. A new type of power system of BCLG coupled with the gas turbine (GT) and ORC was proposed to achieve the high-value utilization of biomass energy. This system achieved the graded utilization of different grades of energy through the material/energy exchange between subsystems. Aspen Plus software was used to simulate the effect of oxygen/biomass ratio (λ) and compressor pressure ratio (PR) on the power generation efficiency of the BCLG-GT system when corn straw, rice straw, and wheat straw were used as gasification fuels, respectively. The simulation results show that straw is the optimal gasification fuel for the BCLG-GT system among the three types of biomass, and the optimal simulation conditions are λ= 0.05 and PR=13. Based on the optimal operating conditions of the BCLG-GT subsystem, coupled with the ORC subsystem, the effects of the four organic fluids (R245fa, R134a, HCFC-123, and R-404A) and regenerative devices on the ORC system were further studied. The simulation results reveal that R245fa has higher practical value and better environmental friendliness, compared with R134a, HCFC-123, and R-404A. The net power output of the ORC system is increased by 13.37% after adding the regenerative device, and the net energy efficiency of the new BCLG-GT-ORC power system with the regenerative device reachs 35.48%. This study provids ideas and theoretical guidance for the design and optimization of BCLG units on an industrial scale.