Abstract: Hogwash oil is always an important factor concerning food safety, and this study aims to establish an effective method to detect hogwash oil. The determination method of cholesterol in hogwash oil is as follows: first, samples are saponificated with anhydrous ethanol and potassium hydroxide in 70℃ water, and extracted with petroleum ether; then, sterol and cholesterol are separated by high performance liquid chromatography (HPLC); at last, clear chromatographic peak are observed under 205 nm. By testing concentrated liquid after filtering, extraction rate of cholesterol exceeds 75%, and the accurate and quantitative detection could be obtained when cholesterol content is over 0.35 g/L. This method is used in blind test, and it could accurately detect the simulation pigwash oil, and traces of cholesterol are found in two kinds of vegetable oil collected from the market.