Abstract:This paper is concerned with analysis of the measurement of the magnetic error calibration of levels and the relevant sources of uncertainty. We analyze the evaluation method of uncertainty for magnetic error calibration of levels. The sources of the uncertainty result from the reproducibility of measurement, the ruling error of micrometer collimator, the reading error, the magnetic field and the fitted linear regression equation for the calibration curve; these sources of uncertaintyare discussed and calculated. The combined standard uncertainty and expanded uncertainty are reported. The results show that the fitted linear regression equation for the calibration curve is an important source of uncertainty.