To evaluate the uncertainty of measurement in the determination of DIBP, DBP and DEHP in Liquor by GC-MS/MS. According to “JJF 1135—2005 Evaluation of Uncertainty in Chemical Analysis Measurement” and “JJF 1059.1—2012 Evaluation and Expression of Uncertainty in Measurement”, a mathematical model was established for uncertainty evaluation. The sources of uncertainty that may be introduced were analyzed and each component of uncertainty was quantified for the calculation of the combined uncertainty, The results showed that the expand uncertainty for DIBP, DBP, DEHP were 0.060, 0.062, 0.17 mg/kg, respectively. The preparation of standard solution, measurement repeatability and curve fitting were found to be the main sources of uncertainty.