Abstract: According to the newly released JJF 1847-2020 “electronic balance calibration specification”, according to the uncertainty measurement model of electronic balance, the factors affecting its uncertainty are analyzed. By controlling various variables, the stable electronic balance in the laboratory is selected as the measured object, and the upper limit, middle limit and lower limit of the coverage range are selected for the evaluation points, so as to form the optimal uncertainty of the laboratory. The uncertainty of electronic balance with different precision and measurement range is summarized, and the interval uncertainty is used to express the laboratory’s ability in a certain measurement range, forming the laboratory’s electronic balance calibration and measurement capability（CMC）.