The CO2 emission from fossil-fuel power plants such as coal-fired power plants is huge, and carbon emission reduction from coal-fired power plants is the only way to achieve the dual-carbon goal. The alkali metal based solid absorbent for CO2 capture has the advantages of low regeneration energy consumption and high selectivity. However, it is very costly to realize carbon capture by the power plant′s own energy, so it is proposed to use trough solar energy to drive magnesium-based carbon capture and regeneration to avoid the efficiency loss of carbon capture in coal-fired power generation, at the same time, the carbonation heat release is used to replace the steam extraction and heating water supply of the power plant, which increases the power generation. Based on the design and analysis of a typical coal-fired power plant development system, the additional power brought by the introduction of trough solar energy and carbon capture system into the design system was calculated, and the total output power of the design system, the single coal-fired carbon capture system and the reference system were compared. The results show that compared with the single coal-fired carbon capture system, the design system avoids 46.4 MW power loss, at the same time, the power generation is increased by 46.2 MW with the aid of heat release from carbonation. The power of the system is increased by 44 MW compared with the simple superposition system of single coal-fired carbon capture and single photothermal power generation, realizing the integration effect of 1+1>2. Taking into account the variation of the solar radiation intensity during a typical day, the system can be designed to avoid the influence of too high/too low radiation on the stability of the system by regulating the carbon capture process, the average carbon capture capacity and the additional power of the system can reach 135.6 t/h and 23.2 MW/h, respectively, realizing the efficient operation of the system under variable working conditions. The system is designed to avoid the loss of efficiency caused by the power plant′s own carbon capture, increase the amount of electricity generated, and achieve efficient use of solar energy and clean use of fossil fuels, which can provide ideas for the low-carbon and high-efficient utilization of the complementary renewable energy and fossil energy.