With the continuous deepening of business activities such as acquisitions， mergers， and equity participation in overseas oil and gas assets， oil and gas reserves have become a key consideration for oil companies. Due to the varying evaluation standards adopted by resource countries， there are significant discrepancies in the estimated reserves. Acquisition activities may involve considerable risks without a precise understanding of these data. Following the strategic cooperation agreements signed between China and the Russian Federation in recent years， oil and gas cooperation projects have been increasingly expanded. It is especially important to refine and clarify the alignment of grading and classification standards for oil and gas reserves/resources between the two countries. This paper analyzed the evaluation， comparison， and result conversion of oil and gas reserves/resources in the context of China’s oil and gas mergers and acquisitions in the Russian Federation and other countries that still adhere to the Russian Federation’s reserves evaluation criteria. It provided a detailed discussion of grading and classification standards for oil and gas reserves/resources currently implemented in both the Russian Federation and China， compared the reserve classification calculation methods and management approaches of the two countries， and identified the similarities and differences between their classification systems.The paper further analyzed the impact of differences in standards on oilfield development， resource evaluation， and technology promotion， offering guidance for professionals to understand better and apply different reserve evaluation methods in practical operations.