Abstract: China–Russia Eastern Gas Pipeline Project is the successful model of deepening cooperation between China and Russia under the Belt and Road Initiative. As a representative project of the cross-border gas transmission pipeline, the pipeline project is of great reference value for its characteristics and experience in preliminary works. The background and significance of China–Russia Eastern Gas Pipeline Project were summarized, the preliminary work processes such as commercial negotiation, pre-feasibility study, feasibility study, project application report preparation, etc. were combed, the special research process focusing on the complex technical and economic conditions of China–Russia Eastern Gas Pipeline Project was introduced, and the innovative achievements of the preliminary works of China–Russia Eastern Gas Pipeline Project were highlighted. The research shows that, for large cross-border energy pipeline projects such as China–Russia Eastern Gas Pipeline Project, its preliminary works may involve multi-level issues in the field of diplomacy, commerce, technology, economy, etc. More manpower, research resources and sufficient time may be required for the smooth implementation of the project.