Abstract: In this study, take measurement of the vitamin B12 in infant formula as an example, measurement uncertainty was evaluated through four calibration methods, including standard addition method, standard addition-isotope dilution mass spectrometry method, single point isotope dilution mass spectrometry method, and standard calibration curve isotope dilution mass spectrometry method. The uncertainty evaluation of the four quantitative methods was assessed based on the ISO-GUM guidelines and other uncertainty assessment methods. The uncertainties introduced by the method of repeatability and curve fitting were the primary sources of uncertainty. Furthermore, the uncertainties obtained by the standard addition method were significantly more significant than those obtained by the isotope internal standard method. The comparative study of different quantification methods can lead to a more effective selection of quantification methods and improved measurement accuracy.