Coal-fired power plants play a significant role in the low-carbon transition of the power system, and retrofitting them can enhance their flexibility while reducing carbon emissions. This paper proposes several retrofit technologies such as coupling compression heat pumps, absorption heat pumps, electric boilers, heat storage tanks, and low-pressure cylinders to address high minimum load rates and weak peaking capacities of heating units leading towards improved flexible operation. Additionally, to reduce energy consumption and save energy for coal-fired power plants, this paper proposes heat supply retrofit, through-flow retrofit and high-parameter retrofit solutions, and analyzes the carbon reduction capability and economics of these schemes. Finally, considering the current situation operational situation of coal-fired power plant in Fujian Province, a multi-path transformation suggestion is given.