In a petroliferous basin with multiple sets of source rocks, determining the origins of hydrocarbons and their mixed ratios is a crucial aspect of hydrocarbon accumulation mechanisms. Focusing on the Mesozoic-Paleozoic reservoirs within the Cangdong Depression, this study began with source-source comparisons to identify key distinguishing parameters. This was followed by oil-oil correlations using the cluster analysis method. And then, oil source correlations were performed to determine the origins of each type of crude oil. On this basis, a quantitative method for predicting the proportion of mixed crude oil sources was proposed. The results show that the Ek