The non-sulfonated oil in industrial petroleum sulfonate was separated by centrifugal method and extraction method, respectively. The oil separation rates of each method were compared, and the effects of oil separation rates under different conditions on the purity of non-sulfonated oil were investigated. The purity information of non-sulfonated oil separated by different methods was analyzed by infrared spectroscopy. The experimental results showed that the oil separation rate of centrifugation was low, and the oil extraction rate was higher. The purity of non-sulfonated oil separated with alcohol-water solution as extractant was lower, while the purity of non-sulfonated oil separated by water extraction method was the highest, and the extractant was nontoxic and environmentally friendly. Water was preferred as extractant. Solvent ratio, temperature and pressure all had great influence on oil separation rate. The optimum conditions for SL petroleum sulfonate were: solvent ratio 1.5:1, 90 degrees C, atmospheric pressure, which the oil separation rate was 78.51%; and for DQ petroleum sulfonate, the optimum conditions were: solvent ratio 2:1, 90 degrees C, atmospheric pressure, which the oil separation rate was 79.86%. Non-sulfonated oil separated by water extraction had the least petroleum sulfonate, followed by ethanol single solvent extraction. Although the extraction efficiency of isopropanol aqueous solution and n-pentane was the highest, the content of petroleum sulfonate in non-sulfonated oil was the highest, which affected the product performance and should not be used.