Abstract: Carbon stable isotopes can be applied to identify the fingerprints of oil spill on the basis that the carbon isotope ratios of the crude oil are generally inherited from their original organic substances. A long-term weathering simulation experiment for the n-alkanes indicators was performed on the 380# fuel oil in the laboratory,δ¹³C_Pr/C19,δ¹³C_Ph/C19,δ¹³C_Pr/C20 and δ¹³C_Ph/C20, its relative standard deviation (RSD) less than 5%, which can be used as diagnostic ratios for the oil source fingerprint identification. For the PAHs indicators, there is a indoor long-term weathering simulation experiments for 380# fuel oil and Kuwait crude oil, the δ¹³C_flu and δ¹³C_ph of the two types of oils were distributed at -27.476‰~-26.583‰ and -26.482‰~-21.914‰, each focusing on a certain range, use of δ¹³C_flu and δ¹³C_phe as double indicators can distinguish different samples of weathering oil in the long-term weathering. Studies have shown that stable isotope tracing oil as a source of technical means can be used to identify the source of oil after weathering.