The invention relates to an evaluation method for a performance index of an electric energy meter. The method, used for evaluating the reliable performance of an electric energy meter, includes the following steps: (1) obtaining factors affecting the normal running of the electric energy meter; (2) conducting a single influence factor test and a complex influence factor test on the electric energy meter in a quantified manner according to the factors affecting the normal running of the electric energy meter; and (3) analyzing the running reliability and stability of the electric energy meter according to a data result of the single influence factor test and a data result of the complex influence factor test, distinguishing sensitive factors that cause an unfavorable influence upon the electric energy meter, and evaluating the overall performance of electric energy metering equipment. Compared with the prior art, the evaluation method has the advantages that the method takes everything into consideration, can be widely applicable, facilitates establishment of an evaluation system, etc.