When capturing CO2 from biomass fired combined heat and power (CHP) plants, the changes in the feedstock and the heat and electricity demands affect the performance of chemical absorption CO2 capture system. To handle such impact, this paper proposed an improved reboiler duty control strategy (control strategy B) based on the evaluation of the control performance of the traditional feedback control strategy (control strategy A) to achieve a constant capture rate. Control strategy B is based on control strategy A, and introduces feedforward compensation based on rich solution flow rate to form a feedforward plus feedback control strategy. This work aimed to find a control strategy suitable for chemical absorption CO2 capture from biomass CHP, by comparing the control performance, capture system performance and flexible operation performance of both control strategies. Based on the dynamic simulations of CO2 capture from actual biomass fired CHP plant, it is found that compared with the control strategy A, the feedforward compensation of the control strategy B can reduce the response time of the reboiler duty to external disturbances, and improve the timeliness and accuracy of the regulation of reboiler duty. The settling time of capture rate is reduced by 54 mins with the control strategy B. Facing the flexible change of capture rate setpoint, the time required for  the stabilization of capture rate is reduced by 57.9% with control strategy B. Under the continuous external disturbance, the capture rate is maintained at ±3% of the setpoint with control strategy B. At the same time, the energy penalty is reduced by 0.14%, and the total captured CO2 is increased by 0.35%. In addition, the results of dynamic simulation and traditional steady-state simulation show that the dynamic simulation can reflect the impact of external disturbances on the capture system more accurately, and provide a reference for the integration and optimization of related processes.