Abstract: Oil-source correlation and origin analysis have been carried out in Mesozoic of the North Yellow Sea Basin based on tests of 6 samples from 4 wells.Correlations of geochemical parameters such as light hydrocarbon composition,chromatogram and mass spectrum of saturated and aromatic hydrocarbon,and carbon isotope of saturated hydrocarbon have indicated that crude oils in the Lower Cretaceous mainly come from the continental fresh water and Ⅱ₂ type source rocks in the Upper Jurassic.The Cretaceous crude oils are similar with the paraffin ones,characterized by naphthene.They are continental mature crude oils with high wax and low sulfur contents,low alum/nickel ratio and good preservation condition.