The invention discloses a method for evaluating energy conservation and emission reduction comprehensive performances of a thermal power generating unit based on a small index integrating system. The method comprises the steps of: acquiring running data of the thermal power generating unit to obtain index data of each item of the thermal power generating unit; calculating score values of net coal consumption rate, station service power consumption rate, primary key control indexes, sulfur dioxide emission concentration, nitric oxide emission concentration and dust emission concentration, so that the unification of the key energy conservation and emission reduction evaluation index system of the thermal power generating unit can be realized; the energy conservation and emission reduction comprehensive benchmarking of the thermal power generating unit can be facilitated; the maximization of the energy conservation and emission reduction comprehensive environmental benefits of the unit can be realized; the unification and comprehensive quantitative analysis of the energy conservation and emission reduction effects of the thermal power generating unit can be realized; the method has good application prospect.