In order to clarify the source, depositional environment and genetic relationship of crude oils in different areas in the northern Melut basin, the geochemical characteristics of crude oils in different areas were analyzed and correlated by means of saturated hydrocarbon chromatography and chromatography-mass spectrometry. The results showed that the n -alkanes of crude oils in the northern Melut basin have no obvious odd-even predominance, the Ts/Tm values range from 1.36 to 3.47, the C₃₁ hopane 22S/(22S+22R) ratios are from 0. 54 to 0. 60, and the ratios of ααα C₂₉20S/(20S+20R) and C₂₉ αββ/(ααα+αββ) are more than 0.4, all of which indicated that the crude oils in the northern Melut basin are mature oils. The gammacerane index is generally less than 0.1, the C₂₁ tricyclic terpanes have obvious predominance, and the values of Pr/Ph range from 0.97 to 2.31, with an average value of 1.61, all of which indicated that the source rocks of these crude oils were formed in the environment of weak reduction-oxidization freshwater lacustrine and developed type II-III organic matter. The source and maturity of crude oils in different areas in the northern Melut basin are different. The crude oils in the eastern slope of the Moleeta sub-sag have a unimodal and post-peak distribution of n -alkane, with a predominance of high carbon number n -alkane and an average value of C₂₄TeT/C₂₃TT being more than 1, which showed that the source rocks of these oils are dominated by terrestrial higher plants. The maturity of crude oil is low, and the heavy-medium oils are generally developed in the eastern slope of the Moleeta sub-sag. The crude oils in the deep area of the Jamous sub-sag have a bimodal distribution of n -alkane, with a pre-peak predominance, and the value of C₂₄TeT/C₂₃TT is less than 1. In addition to the contribution of terrestrial higher plants, the aquatic organisms also have an important contribution to the source rocks. The maturity of crude oil is relatively high, and the medium-light oils are generally developed in the deep area of the Jamous sub-sag. The Palogue oilfield is located between the two hydrocarbon-generating sub-sags and has the characteristics of mixed sources. The crude oils of the AYT oilfield mainly comes from the deep area of the Jamous sub-sag, and also has the contribution of local source rocks. The tilting fault zone in the middle part of the eastern slope of the Jamous sub-sag divided the sub-sag into two secondary faulted depressions, which provided the structural conditions for the deposition of local source rocks in the AYT(Abyat) area. Meanwhile, the tilting fault zone uplifted and shallowed the middle part of the Jamous sub-sag slope, where the shallow-water sandstone and mudstone interbeds locally developed in a weak oxidization environment.