Abstract: Three different decarbonization operational modes for coal-fired power plant under various power outputs and CO₂ capture rate constraints were proposed. A thermo-economic analysis was conducted on a typical 600 MW coal-fired power plant under these three decarbonization modes, so as to obtain the optimal decarbonization strategy for the power plant in varying scenarios of electricity prices, coal prices, and carbon taxes. Results show that constant power mode minimizes energy consumption penalties for the power plant, yet it fails to meet stringent CO₂ capture requirements across all operating conditions. For the reduced power mode and constant power mode, when the grid electricity price falls below 0.371 yuan/(kW·h) or the coal price is below 682.45 yuan/t, the reduced power mode offers greater additional economic benefits. When electricity prices range is 0.371-0.407 yuan/(kW·h) or coal prices is between 682.45 and 758.94 yuan/t, the appropriate operating mode should be selected based on the unit's load. If the electricity price is higher than 0.407 yuan/(kW·h) or the coal price is below 682.45 yuan/t, and the unit load is below 93%, the constant power mode yields higher returns.