A principal component analysis based electric power project assessment method is characterized by comprising the steps that S1, the names and number m of projects to be assessed are determined, and assessment criterions and number p are determined; S2, an assessment model is established by adopting a component analysis method to determine the assessment criterions, wherein the number of the new assessment criterions is smaller or equal to 2, two of the new assessment criterions are uncorrelated or are mutually independent when the new assessment criterions are 2; S3, project assessment is performed according to the new assessment criterions in the step S2.The principal component analysis based electric power project assessment method can achieve interpretation of most of variations in original information with less variables and convert lots of variables having very high correlation into mutually independent or uncorrelated variables.The principal component analysis based electric power project assessment method is a method for performing comprehensive assessment completely according to assessment results of projects under criterions without regard to criterion weight and subjective preference of an assessor.