To improve the natural gas heating supply capacity, distributed heat pump peak-shaving technology has great potential to be further studied and promoted. This technology is to use heat pump to adjust heat on the secondary network in substation, simultaneously, to reduce the return water temperature of primary network by using the principle of heat pump. Return water of primary network with low temperature creates favorable conditions to recover waste heat in heat source, and improve heating efficiency. This paper takes a set of two 9F gas-steam combined cycle back pressure heating unit as an example and evaluates its feasibility and application effect. It is compared with a general gas boiler peak-shaving system on the design and operation condition. For comparison, fuel consumption of these two heating systems are almost the same. Heating energy consumption of new system is reduced by 6%. Dynamic investment-increment payback period is 3.1 years, meaning that the new system has good economy. The research shows that the system can improve network transmission and distribution capacity, increase heating capacity and reduce heating energy consumption. And it also can ensure the safety of heating.