Abstract: Although traditionally it is very difficult for high molecular weight hydrocarbons micro-leaking to the surface, existing research shows that high molecular weight hydrocarbons can seep to modern surface sediments. Based on their different geochemical characteristics, modern sediments of the Yellow Sea and typical crude oil have been matched with different ratios to study the composition of each product. Results show that with the increasing proportion of oil in the matching test, the chromatographic fingerprint of n-alkanes and part of aromatic hydrocarbons show regular changes. The OEP of the n-alkanes disappear gradually and the abundance of alkyl aromatic hydrocarbons increases. The absolute concentration of the compounds, such as Tricyclic terpane, hopanes, regular steranes, and ratio of dibenzothiophene versus phenanthrene also show regular changes. Tricyclic terpane, ratio of C₂₄ tetracyclic terpane alkyl/C₂₆ tricyclic terpane and ratio of ricyclic terpanes/hopane change smoothly and obviously with a range of 0-3.0, suitable for building a leakage plate. In the case of excluding external pollution, comparison of unknown samples collected in the study area with the matched mixture can determine whether there is an oil and gas reservoir. Plotting the same indices of the unknown samples on the plate would further quantitatively identify the proportion of crude oil in the sediment sample. This method can be used as a supplement to conventional exploration for oil and gas and can give much more information about reservoir evaluation. This method can alsobe extended to the field of environmental pollution monitoring.