The invention discloses a method for evaluating the economic performance of a power plant. The method includes the first step of collecting scoring data of economic performance indexes, the second step of using the economic performance of the power plant as a matter-element to be evaluated, converting the indexes to characteristics of the matter-element to be evaluated and using a matter-element model to describe the economic performance of the power plant, the third step of establishing a classic domain model of the economic performance matter-element to describe demand intervals of the economic performance indexes with respect to quantity value ranges of various category levels, the fourth step of establishing a section domain model of the economic performance matter-element to describe scoring ranges of the economic performance indexes, the fifth step of calculating the correlation degrees between the economic performance indexes and the various category levels according to a primary correlation function, the sixth step of determining weighting coefficients of the economic performance indexes, and the seventh step of calculating the correlation degrees between the economic performance and the various category levels through a weighting summation mode, and judging the level that the economic performance of the power plant belongs to according to the maximum value of the correlation degrees. Through the method, the economic performance of the power plant can be scientifically evaluated.