City central heating system for gradient utilization of large temperature difference

The utility model belongs to the technical field of central heating equipment, and relates to an urban central heating system for gradient utilization of large temperature difference. Comprising an absorption heat pump, a water source heat pump set, a primary network system, a secondary network radiator system and a secondary network floor heating system, the absorption heat pump and the primary network of the water source heat pump set are connected in series, and the secondary network is connected in parallel for operation, so that the return water temperature of the primary network can be effectively controlled below 10 DEG C; and according to the difference of the water supply temperature of the secondary network improved by the hot water type absorption heat pump and the water source heat pump set, the requirements of different design temperatures of the radiator and the floor heating system can be met at the same time, and the large temperature difference technology of the primary network is improved to