Abstract: The North Yellow Sea basin is one of China’s low degree of prospecting area where the crude oil found at present is produced in Lower Cretaceous. It has the characteristics of high density, mid?high wax and low sulfur, belonging to typical lacustrine mature crude oil, without obvious biological degradation. The GC, GC?MS and carbon isotope composition analyses of the crude oil and the Middle and Upper Jurassic source rocks are conducted and the oil?source correlation is made in this paper. The results indicate that the characteristics of the carbon isotopic composition, isoprene, terpane and sterane biomarker, stable carbon isotopic compositions of the individual n?alkanes are different from the Middle Jurassic source rocks. The crude oils could come from the lacustrine mature source rocks with good kerogen type and parent materials dominated by low aquatic organisms