Alkans was selected and its oxidation in supercritical water was investigated. The experimental results showed that when the reaction temperature is 420??C, pressure is 24 MPa, the residence time is 10 min, and the alkane removal of oilfield sludge could reach 96.4%. The residence time and reaction temperature are the main factors for alkanes removal of oilfield sludge. The removal increases with the rise of reaction temperature and residence time. Reaction pressure and original concentration of oxygen are also important, but when the reaction pressure and oxidant concentration reach a certain value, the crude oil removal changes little.