The invention relates to a construction method of a thermal power plant power environment-friendly index model. The method is technically characterized by comprising the following steps of performing online acquisition of carbon and pollutants of a power generator set, and calculating the environment value of the carbon and the pollutants which are directly discharged from the thermal power plant; calculating the environment value of the carbon and the pollutants which are indirectly discharged from the thermal power plant according to the field power consumption amount of the thermal power plant; calculating a power environment-friendly degree and power environment-friendly index of the thermal power plant, and constructing a power environment-friendly index grade model of the thermal power plant. The construction method realizes reasonable designing and can accurately calculate the power environment-friendly index of the thermal power plant in a monitoring time period. According to the power environment-friendly index, not only can environment-friendly operation and development conditions of different thermal power plants be dynamically evaluated, but also the international energy-saving and omission-reduction condition of the current thermal power is vividly calculated through calculating the power environment-friendly index grade of the thermal power plant for facilitating transverse comparison and longitudinal comparison. The construction method can be utilized for monitoring the environment-friendly development operation of the thermal power plant and furthermore supplies important theoretical basis for making a thermal power plant environment-friendly development standard by Chinese government.