Abstract: In order to solve the problem of residual energy loss of bypass steam in the process of temperature and pressure reduction in the normal pressure bypass heating system, a new bypass heating system connected to the bypass heating system was proposed. By adding a steam ejector, the bypass steam is injected into the steam turbine exhaust steam to provide heat, which not only reduces the energy cascade utilization, but also causes a loss of cold source in the central air conditioner. Taking a 300MW combined heat and power central air conditioner as the research object, a thermodynamic calculation model of air conditioner central air conditioner was established using EBSILON to conduct a comprehensive analysis of the peak shaving capacity, thermal performance and economy of the new bypass heating system. The results show that compared with the conventional bypass system, the heating capacity of the new bypass system increases by 97.26 MW, and the minimum electric load rate decreases by 0.14. Under the same electric heating load conditions, the new system's power generation thermal efficiency increased by 19.4%, saving 9.2 tons of standard coal per hour, and the annualized net present value of income increased by 2.16 million yuan, with higher economic benefits and promotion value.