Circulating water heat pump combined steam residual pressure utilization graded heating system and adjusting method

The invention discloses a circulating water heat pump combined steam residual pressure utilization graded heating system and an adjusting method. The system comprises a steam extraction heat supply subsystem, a steam residual pressure utilization subsystem, a circulating water heat pump subsystem and a tail end user subsystem, wherein the steam extraction heat supply subsystem, the steam residual pressure utilization subsystem and the circulating water heat pump subsystem are connected in series, and the tail end user subsystem is used for heating heated heat supply network water. The steam extraction heat supply subsystem comprises a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder of a steam turbine. A heating network heater is connected to a heating steam extraction pipeline of the medium-pressure cylinder and connected to the tail end user subsystem through a heat supply network water supply pipeline. A heat supply network heater steam inlet adjusting valve is arranged on a s