The regeneration of waste lubricating oil was carried out under the conditions of temperatures 383K, 423K and 473K, and 8.0-16MPa pressure range by using propane solvent at supercritical condition. The contents of impurities and heavy metals contaminated in the refined oils that were regenerated at all the experimental conditions were fully satisfied the environmental criteria when used as fuel. The extraction yield was up to about 85%, according to the increase of pressure, but the optimum condition was likely to be that of 423K and 10MPa, considering the physical properties such as color and impurity contents in the refined oil.