Abstract: To identify hydrocarbon potential of the Carboniferous source rocks in Beisantai swell of Junggar basin, abundance, type, maturity and distribution of organic matter in Carboniferous tuffite and dark shale in the study area are correlated and analyzed on the basis of geochemical parameters such as rock pyrolysis, carbon isotope and biomarkers, etc., based on which oil-source correlation and analysis are carried out. The result shows that the Carboniferous tuffite and dark shale have relatively high organic matter abundance with organic matter type dominated by Type Ⅱ2-Ⅲ that have entered into the matured phase of large amount of oil and gas generation. The tuffite mainly occurs in the central Beisantai swell and is a set of thick and moderate-good quality source rocks. The dark shale is of less thickness, which may constrain the rock to be the key source rock. The results of oil-source correlation and analysis also exhibit that the oil in Xiquan-3 reservoir is sourced from the Carboniferous tuffite, which can further verify the capability of hydrocarbon generation and expulsion of this tuffite as effective source rocks