Abstract: The existing error test method of the itemized measurement of electric energy is simulated through the digital simulation system,in which the detailed quantitative analysis is not realized, resulting in low error measurement accuracy.Therefore,a new method of the itemized measurement of electric energy under the influence of harmonics is proposed in this paper. The working principle of the itemized electric energy metering system is analyzed. According to the working principle of the potential transformer,the additional error caused by harmonic is obtained. Using the equivalent circuit of the current transformer,according to the law of magnetic flux conservation and Kirchhoff current law,the error test results of the current transformer are obtained. The error of the electronic watt hour meter under the influence of harmonic is tested by a multiplier.The sum of the errors of the potential transformer,current transformer and electronic watt hour meter under the influence of harmonics is regarded as the partial metering error of electric energy. The experimental results show that the measurement error of the proposed method is consistent with the actual error value,providing a reliable basis for the accurate measurement of the electric energy.