The invention provides an electric power replacement technology comprehensive benefit assessment method based on a comprehensive weighting method. The method comprises the following steps: 1) constructing an electric power replacement technology comprehensive benefit assessment index system architecture; 2) calculating objective weights of four-level index layers in the system architecture according to an entropy theory; 3) calculating each factor weight vector of second-level rule layers, three-level index layers and the four-level index layers in the system architecture; 4) calculating comprehensive weights of elements in the four-level index layers in the system architecture; and 5) carrying out analysis evaluation on the system architecture. Various factors influencing electric power replacement technology comprehensive benefits are taken into overall consideration in the technical performance aspect, environmental effect aspect, economic benefit aspect, power grid operation aspect, thereby maximizing the comprehensive benefits introduced by the electric power replacement technology.