Abstract:Toestablish a method for the determination of N-dimethyl nitrosamine in meat by gas chromatogra－ phy/triple level 4 pole mass spectrometry. Meanwhile， analyzing and evaluating the uncertainty which was prop－ erly occurred during the method. Samples were extracted by QuEChERS method， which followed by qualitative and quantitative analysis using MRM model. According to set up the mathematical model for the uncertainty e－ valuation， it confirmed and simplified the source of uncertainty， as well as calculated the combined uncertainty and the expanded uncertainty. The range of recovery rate with standard solution was 87.8 % to 115.3 % ，relative standard deviation（RSD） was 4.3 % to 6.2 % and the linearly dependent coefficient was 0.999 5. It was showed that there were 5 samples were positive samples（there were 15 samples totally） and the content of those all five samples were lower than the national limited value which was 3.0 μg/kg. The content of N-dimethylnitrosamine was （3.0±0.18）μg/kg and the relative expanded uncertainty was 6.0 % under the condition of detecting 3.0 μg/ kg.Conclusionit could be found that this method was easy， high sensitivity， better repeatability， lower organic solvent consumption and satisfying the requirements of national trace detection. Thus， this method can be used in the uncertainty evaluation during the determination of N-dimethylnitrosamine by GC-MS/MS.