The invention discloses a circulating system of an outer culvert heat regeneration gas turbine, and relates to the technical field of gas turbines. The circulating system of the outer culvert heat regeneration gas turbine comprises a high-pressure turbine, a low-pressure gas compressor, a high-pressure gas compressor, an air turbine, a turbine component, an afterburning combustion chamber and a heat regenerator, wherein the afterburning combustion chamber is arranged between the high-pressure turbine and the turbine component; gas exhausted by the high-pressure turbine enters the afterburning combustion chamber for further burning; the temperature of gas entering the turbine component is increased; the exhaust temperature of the turbine component is increased; a heat regenerator absorbs heat in exhausted gas of the turbine component; and outer culvert gas exhausted after the compression by the low-pressure gas compressor is heated. The circulating system has the following benefits: the afterburning combustion chamber is added in the circulating system of the outer culvert heat regeneration gas turbine, so that the temperature of the gas exhausted by the turbine component is higher; and the heat regenerator recovers the exhaust temperature of the turbine component, and heats the outer culvert gas exhausted by the low-pressure gas compressor, so that the power and the heat efficiency of the gas turbine are improved.