Abstract: In order to reduce the influence of solar energy fluctuation on the performances of the solar-coal complementary power generation system, a new type of solar-coal complementary power generation system was proposed. Models of key devices and subsystems were developed and verified, and the thermal and techno-economic performances of the new solar-coal complementary power generation system were studied. Results show that the thermal performance of the system decreases with the operation load, and increases firstly and then decreases with the increase of direct normal irradiance. The average annual output power of the system is 699 MW, the average annual coal saving rate is 7.506 g/(kW·h), and the average annual solar-to-power efficiency is 10.82%. When the heat storage capacity duration is 10 h, the system has the best techno-economic performances, with the life-cycle net present value of 4.18×10⁸ yuan, the internal return rate of 11.81% and the dynamic payback period of 12.6 years. The levelized cost of electricity is 0.402 yuan/(kW·h), and the profitability is good.