A gas-steam combined cycle centralized heat supply device, the gas-steam combined cycle centralized heat supply device comprises a gas-steam combined cycle system, a heating network return water heating system and a thermal station, the gas-steam combined cycle system is connected with the thermal station through the heating network return water heating system; the gas-steam combined cycle system comprises a gas turbine, a waste heat boiler, a direct contact type flue gas condensation heat exchanger and a steam turbine; an exhaust port of the gas turbine is connected with a flue gas inlet of the waste heat boiler; a flue gas outlet of the waste heat boiler is connected with a flue gas inlet of the direct contact type flue gas condensation heat exchanger, a steam outlet of the waste heat boiler is connected with an extraction steam inlet of the steam turbine, the heating network return water heating system comprises a steam type absorption heat pump for recovering flue gas waste heat, a steam-water heat exchanger and a power plant water-water heat exchanger, characterized in that a drain water inlet of the waste heat boiler is connected with the heating network return water heating system; a first intermediate medium water inlet, a first intermediate medium water outlet, a second intermediate medium water inlet and a second intermediate medium water outlet of the direct contact type flue gas condensation heat exchanger are connected to the heating network return water heating system; an extraction steam outlet of the steam turbine is connected to the heating network return water heating system; the thermal station comprises a hot water type absorption heat pump and a water-water heat exchanger, a heating network return water outlet and a heating network supply water inlet of the hot water type absorption heat pump are connected to the heating network return water heating system, a heating network supply water outlet of the hot water type absorption heat pump is connected with a heating network supply water inlet of the water-water heat exchanger, and a heating network return water inlet of the hot water type absorption heat pump is connected with a heating network supply water outlet of the water-water heat exchanger, a heating network water inlet of the power plant water-water heat exchanger is connected with the heating network return water outlet of the hot water type absorption heat pump, and a heating network water outlet of the power plant water-water heat exchanger is connected with a heating network water inlet of the steam type absorption heat pump for recovering flue gas waste heat; a heating network water outlet of the steam type absorption heat pump for recovering flue gas waste heat is connected with a heating network water inlet of the steam-water heat exchanger, and a heating network water outlet of the steam-water heat exchanger is connected with the heating network supply water inlet of the hot water type absorption heat pump; an intermediate medium water outlet and an intermediate medium water inlet of the steam type absorption heat pump for recovering flue gas waste heat are respectively connected with the first intermediate medium water inlet and the first intermediate medium water outlet of the direct contact type flue gas condensation heat exchanger; an intermediate medium water outlet and an intermediate medium water inlet of the power plant water-water heat exchanger are respectively connected with the second intermediate medium water inlet and the second intermediate medium water outlet of the direct contact type flue gas condensation heat exchanger; and a drain water outlet of the steam type absorption heat pump for recovering flue gas waste heat and a drain water outlet of the steam-water heat exchanger are connected to the drain water inlet of the waste heat boiler, and an extraction steam inlet of the steam type absorption heat pump for recovering flue gas waste heat and an extraction steam inlet of the steam-water heat exchanger are connected to the extraction steam outlet of the steam turbine.