The invention discloses a power generation system capable of improving heat conversion efficiency, and belongs to the technical field of a heat conversion power generation system. The problem of a current power generation system that heat efficiency is low because of heat waste can be solved. The power generation system comprises a heating circulation system and a heat conversion system, wherein the heating circulation system is a heating and heat storage circulation system which takes solar energy as a heat source or a heating circulation system which takes natural gas or pulverized coal as heat source fuel; the heat conversion system comprises a heating circulation system, an expansion machine, a backheating heat exchanger, a cooler, a compressor and a power generator; an outlet of the heating circulation system is connected with an inlet of the expansion machine; an outlet of the expansion machine is connected with a high-temperature-end inlet of the backheating heat exchanger; a low-temperature-end outlet of the backheating heat exchanger is connected with the inlet of the compressor through the cooler; the outlet of the compressor is connected with the low-temperature-end-inlet of the backheating heat exchanger; and the high-temperature-end outlet of the backheating heat exchanger is connected with the inlet of the heating circulation system. By adopting the power generation system, the heat efficiency of the power generation system is improved.