Abstract: The southern margin of Junggar Basin is characterized by various anticlines, widespread hydrocarbon, diversified hydrocarbon properties, as well as five sets of effective source rocks and extremely complex oil-source relation, so that a large dispute exists in crude oil source for a long term. Five sets of source rocks and crude oil samples from different structures were systematically collected in this study, and comprehensive correlation analyses were carried out on the carbon isotopes of source rock extracts, crude oil, n-alkanes and isoprenoid alkanes and their biomarker component characteristics. The results show that four types of crude oils in the southern margin are derived from source rocks in different periods. The first type of crude oil is characterized by light carbon isotopes, relatively flat distribution of carbon isotopes of individual n-alkanes, abundant β-carrotane, as well as sterane dominated by C₂₈ and C₂₉ regular sterane, derived from Permian source rocks. The second type of crude oil is characterized by heavy carbon isotopes, relatively flat distribution of carbon isotopes of individual n-alkanes, high Pr/Ph ratio, sterane dominated by C₂₉ regular steranes and diasteranes, tricyclic terpane dominated by C₁₉ and low content of gammacerane, derived from Jurassic coal measures. The third type of crude oil is characterized by light carbon isotopes, molecule carbon isotopes of n-alkane largely reduced with increasing carbon numbers, the ratio of Pr/Ph less than 1.0, V-shaped distribution of C₂₇, C₂₈ and C₂₉ sterane, and a high content of isocholestane, diasterane, Ts, C₂₉Ts, C₃₀ diahopane and gammacerane, derived from the source rocks of Cretaceous Qingshuihe Formation. The fourth type of crude oil is characterized by heavy carbon isotopes, molecule carbon isotopes of n-alkane greatly reduced with increasing carbon numbers, V-shaped distribution of C₂₇, C₂₈ and C₂₉ sterane dominated by ααα-20R, and abundant dinosteranes, derived from the source rocks of Paleogene Anjihaihe Formation. At present, no crude oil has been found derived from the Triassic source rocks in the south margin.