With the increasing proportion of new energy in China's energy supply, its inherent volatility will bring severe challenges to the power system, and the system needs more flexible resources to meet the demand of system balance. As a kind of high-quality flexible regulating resource, conventional thermal power unit is crucial for integrating a high proportion of renewable energy. In view of the decline in the guaranteed income of thermal power units, China currently implements a two-part electricity price policy for coal-fired power units to ensure the basic income of conventional thermal power units, but it cannot effectively encourage thermal power units to further improve their regulation performance. Based on the comparative analysis of the applicability of typical capacity compensation methods at home and abroad in China's market environment, a double-differentiated capacity compensation method considering cost recovery and flexible adjustment is proposed, including two compensation methods: guaranteed cost recovery capacity compensation and incentive flexible adjustment capacity compensation, and the corresponding compensation intensity calculation model is established. This method uses universal evaluation index to help thermal power units recover costs more accurately, and can also motivate them to further improve their flexible regulation performance. Finally, simulations using the IEEE 30-node system validate the effectiveness of this compensation method in fixed cost recovery, flexible regulation capability incentives, and supporting system stability.