Abstract: A method for the high-sensitive determination of mineral oil hydrocarbons (MOH) in vegetable oil-based canned fish was established, and applied in some commercial products. The samples were extracted and purified by saponification and epoxidation, and were fractionated, concentrated and quantitatively determined by on-line high performance liquid chromatography coupled with gas chromatography (HPLC-GC) for mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The results showed that the limit of quantification (LOQ) of the method was 0.5 mg/kg and the spiked recovery was 90.0%~106.0%, and the precision (RSD) was 1.6%~12.7%, which met the requirements of the European Joint Research Center (JRC) for the analysis of MOH in the higher-fat/oil-content foods. This method was applied to detect ten canned fish products sold in Beijing. It was found that all of those contained MOSH with contents of 2.6~53.7 mg/kg, of which five detected MOAH with a content of 0.7~5.5 mg/kg. The MOH chromatographic profiles indicated that the contaminants were closely related to the sources of the vegetable oils and fish meat in those products.