In this paper, the Fapas ability was used to verify the chloramphenicol residues in shrimp meat by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the uncertainty was evaluated. Uncertainty was given. First, a mathematical model for determining the uncertainty of chloramphenicol residues in shrimp was established, and then the source of uncertainty was analyzed. The uncertainty of the uncertainty was 0146 2 μg/kg (k = 2) when the chloramphenicol residues in the shrimp were 0.820 8 μg/ kg, and the results were in accordance with the Fapas ability test. Specify the scope. The results showed that the UPLC-MS / MS method was used to determine the uncertainty of the process of determination of chloramphenicol in shrimp，sample weighing, sample extraction, calibration curve, mass spectrometry and calibration curve etc were the major infact for uncertainty. The standard series solution formulation and the fitting of the standard curve were introduced with the greatest uncertainty.