Crude oil and hydrocarbon source rocks contain a series of compounds that play a pivotal role in identifying the depositional environment of hydrocarbon source rocks, determining the maturity of oil and gas, and analyzing the origin of oil and gas. These identification indicators are usually constructed based on the ratio of relative content of biomarker compounds. However, as the maturity of the hydrocarbon source rock increases, the content of biomarkers will significantly decrease, leading these ratio indicators to fail in accurately reflecting the true geological information. In contrast, the absolute content changes of the compounds contain richer information, providing valuable clues for oil and gas reservoir research. This paper conducted an in-depth study of the absolute quantitative technology of compounds in hydrocarbon source rocks and crude oil, taking the Dongying sag as a case study, and explored the application of this technology in oil and gas research. Through the self-developed biomarker enrichment device and improved pre-treatment method, an online low-speed centrifugal separation technology for hydrocarbons was established, effectively solving the problems of long analysis cycle, easy loss of light components, and low recovery rate in the past. By carefully selecting the diluent, a low abundance full series of hydrocarbon enrichment technology was developed, achieving accurate quantitative detection of low abundance compounds. In addition, by selectively screening different internal standard compounds, a precise absolute quantitative analysis technology for the full series of compounds was established, achieving quantitative detection of the full series of compounds. The study clarified the change rules of the content of different series of compounds as the maturity increases. Quantitative analysis of compounds was carried out in the hydrocarbon source rocks and crude oil samples of the Dongying sag. The data analysis results show that the content of different types of compounds will change regularly with the increase of maturity. Based on these changes, oil and gas maturity identification and source analysis can be carried out. Combined with mathematical statistical analysis methods, it is also possible to determine the end-member oil components of mixed-source oil and their proportions. The research results show that the quantitative analysis technology of biomarker compounds has important application value in the reservoir research of deep buried high maturity oil and gas.