Abstract: Liquidliquid Extraction (LLE) with n-hexane was developed to extract 12 kinds of semi-volatile organic compounds in groundwater samples. Gas chromatography equipped with electron captured detector (ECD) and high performance liquid chromatography equipped with ultraviolet detector (UVD) and fluorescence detector (FLD) were used to analyze the target compounds. Some factors affecting the determinations including the preservation of the water samples, the activity evaluation of the gas chromatography injection, inspection of reagent blanks, elimination of emulsification in water sample extraction, etc. were discussed in details. Reference to the QA/QC protocols from EPA, a quality control procedure for semivolatile organic compound analysis in groundwater samples was proposed. By using quality control charts for evaluating batch analytical results, it ensures that the analytical procedure is under the quality control.