A fast and easy multi-pesticide residue analyzing method for 73 and 19 pesticides in tobacco by LC-MS/MS and GC-MS respectively was introduced. The matrix effects and the deviations of detecting results were discussed as the main points of this thesis in several approaches. Firstly, the contributions of different tobacco types to matrix effects were compared, including burley, oriental and flue-cured tobacco samples. Secondly, the influences of dilution on matrix effects were shown as different detecting responses along with dilution times, which illustrated that proper dilution could minimize matrix effects, although not completely. Thirdly, the moisture content of the sample was regarded as one of the factors affecting extraction efficiency and matrix effects. The addition of moisture to the dried sample benefited the extraction and minimized matrix effects. However matrix effects could not be minimized only by using an internal standard because the matrix affected each analyte differently. Therefore matrix-matched standard solutions were necessary. By investigating the influencing factors of matrix effects and how to minimize them effectively, the detection results of the multi-pesticide residue analyzing method were improved.