Abstract: According to the evaluation and expression method of measurement uncertainty, a mathematical model for evaluating the uncertainty of determination of vanadium in graphite samples by inductively coupled plasma mass spectrometry was established, and the uncertainty components were analyzed. When the content of V₂O₅ in graphite samples was 0.215%, the expanded uncertainty was 0.035%. Through analysis, it is found that curve fitting, recovery and repeatability test have great influence on the results.The method can provide theoretical basis for the accuracy and confidence of the determination results of vanadium in graphite samples.