The flexible operation mode of carbon capture equipment has brought more operation control strategies to the carbon capture plant.The concept of relative capture degree is defined based on the flexible operation mode.The formula is derived under the flexible operation mode according to the relative capture degree.The start energy consumption formula of the carbon capture equipment is given.By taking the emission reduction and coal consumption of generators as the objective function，the multi-objective bacterial colony chemotaxis algorithm is used to optimize the objective function based on the relative capture degree.At the same time，the optimal percentage of output between the generators is completed.Finally，simulation test is carried out in a carbon capture plant.By comparing the basic running mode with the flexible operation mode，the concept of proportion of emission reduction to coal consumption is given to analyze the result of optimization.Simulation results have proved the effectiveness of the proposed method.