The invention discloses a refuse gasification fuel and steam turbine combined power generation-based CO2 reclaiming system, which comprises a refuse gasification system, a boiler system and a power generation system, wherein the power generation system comprises a mixer, a low-pressure air compressor, a high-pressure air compressor, a synthesized gas compressor, a synthesized gas combustion chamber, a turbine motor a, a turbine motor b, a steam turbine, a power generator a, a power generator b, a residual heat boiler, a gas-water heat exchanger, an air-vapor heat exchanger, a synthesized gas-vapor heat exchanger, a circulating fan, a first separator, a second separator and a water supply importation system; the second separator is used for separating CO2 and N2, remaining vapor is input into the synthesized gas compressor, and the remaining gas separated by the first separator is input into the refuse gasification system as a gasifier. The reclaiming system can conduct large-scale continuous refuse gasification treatment, the recovery efficiency of heat is high, regenerable chemical raw materials can be extracted, and the near zero emission of pollutants and CO2 can be effectively realized.