The invention provides a heat pump heat supply system and method suitable for peak regulation of a heat power plant. The peak regulation effect can be achieved, and waste heat of a steam turbine generator can further be sufficiently recovered to increase the energy utilization rate. The heat pump heat supply system comprises a heating network circulating water return pipeline, a heat pump, a heating network heater and a heating network circulating water supply pipeline. The output end of the heating network circulating water return pipeline communicates with the heating network circulating water input end of the heat pump, the heating network circulating water output end of the heat pump communicates with the heating network circulating water input end of the heating network heater, and the heating network circulating water output end of the heating network heater communicates with the heating network circulating water supply pipeline. The heat pump is driven electrically, and a driving source is led from the steam turbine generator. A low-temperature heat source of the heat pump is provided by the steam turbine generator. According to the heat supply method, heating network circulating water is delivered to the heat pump, the heat pump is driven by electric energy generated by the steam turbine generator, dead steam or circulating water output by the steam turbine generator isadopted as a low-temperature heat source to heat the heating network circulating water, and then the heating network circulating water is further heated by the heating network heater and then output.