This experiment studied the variation of phthalic acid esters(PAEs) and polychlorinated biphenyls(PCBs) in fish oil refining process by establishing a detection method of gas chromatography-mass spectrometry (GC-MS).The samples were dissolved by n-hexane-methylene chloride,purified by florisil and then determined by GC-MS.The results showed that original oil samples contained little PAEs(DIBP,DBP and DEHP)and polluted in refining process.The content of DIBP,DBP and DEHP increased with the refining process,DIBP was from 0.06 mg/kg to 0.19 mg/kg and increasing rate was 216%,DBP was from 0.05 mg/kg to 0.24 mg/kg and increasing rate was 380%,DEHP was from 0.04 mg/kg to 0.06 mg/kg and increasing rate was 50%.It could be preliminarily inferred that industrial additives used in the refining process were the main pollution sources of PAEs.Fortunately,there was no polychlorinated biphenyls determined in the original oil and refining process.The recovery experiment for PCBs indicated that recovery rate was between 72.4% to 78.4%,the relative standard deviation was between 2.6% to 5.1%.