Abstract: The measurement uncertainty of benzoic acid in wine by high performance liquid chromatography ( HPLC) was evaluated.According to the basic principle and method given in GB/T 5009.29-2003 Determination of sorbic acid and benzoic acid in foods, the components of uncertainty in the measuring process were studied and analyzed as the procedure for uncertainty assessment described in CNAS- GL06 Guidance on Evaluating the Uncertainty in Chemical Analysis and JJF 1059-1999 Evaluation and Expression of Uncertainty in Measurement.And the combined uncertainty was calculated and evaluated using achieved results and related data. The results showed that the major factors of uncertainty in measurement were standard solution and HPLC, and the minor ones were measurement repeatability and pipetted volume of sample separately.