Objective Oil supply security is essential to national energy security. Despite China’s transition to high-quality energy development, oil demand will continue to be significant for the foreseeable future, and supply security remains a critical concern. Establishing an evaluation system for oil supply security, analyzing key influencing factors, and conducting comprehensive evaluations are crucial for informing national energy security strategies and policies.

Methods Drawing on the entire oil industry chain—including production, storage, transportation, and marketing—11 key indicators across five dimensions (“resources, transportation, reserves, production, and consumption”) were selected to establish a comprehensive “5-dimension and 11-indicator” oil supply security evaluation system. Using data from eight countries between 1980 and 2024, principal component analysis was conducted to examine oil supply security indicators over an extended historical cycle. The entropy weight method was employed to assign weights to these indicators, enabling a quantitative evaluation of oil supply security for various countries and a review of the historical evolution of China’s oil supply security during this period.

Results Five indicators—external dependence, economic complexity index, oil’s share in primary energy, oil consumption intensity, and shipowner tanker capacity—demonstrated strong correlations with oil supply security, with weights of 11.90％, 11.26％, 11.13％, 10.65％, and 10.37％, respectively. China’s oil supply security score ranged from 0.46 to 0.57, indicating general security, second only to the United States, with the gap steadily narrowing. China benefits from multiple stable oil import channels, reflected in a resource concentration index around 0.09, minimizing vulnerability to external disruptions. Improvements in national oil transportation and overall national strength have significantly enhanced the security of imported oil transport, while increased reserves and production have bolstered the inherent security of domestic oil production. Additionally, the ongoing energy transition has led to a consistent decline in both the share and intensity of oil consumption in primary energy use, reducing the associated security risks.

Conclusion On the basis of consolidating a diversified oil supply pattern, expanding the share of Chinese shipowners’ tankers will enhance oil transportation security; promoting domestic oil reserves and production will strengthen production security; and accelerating the energy transition and optimizing the consumption structure will improve oil consumption security.