As an important part of HVDC system, the accuracy of HVDC energy measurement has a direct impact on the power settlement and related technical index calculation. Aiming at the typical HVDC energy measurement system, considering the accuracy level of each device in the system and the probability distribution of the error, combined with the actual energy measurement algorithm used in the project, the error model of HVDC energy measurement is established. The simulation analysis shows that the relative error of DC power metering system is related to the mean value of error distribution of each link under the condition of different device accuracy level combination, and the relative error of total power on DC side is related to the mean value of positive and negative power metering error of converter unit. The error of DC energy meter is tested in the converter station, and the measurement error of DC energy meter is obtained. As the overall error caused by the combination of devices will have a certain impact on the loss energy measurement of the DC transmission system with a small loss rate of the system, it is necessary to increase the number of periodic calibration tests on the basis that the measurement device meets the accuracy level, and reduce the mean error of the device as much as possible in the calibration process, so as to improve the accuracy of the high-voltage DC energy measurement.