To explore the impact of the signing of RCEP on China’s industrial chain and supply chain from three aspects：the principle of cumulative value added，positive and negative lists of differentiation，and China-Japan-Korea strategic cooperation. On this basis，according to the international trade theory of goods trade creation and transfer effect，service trade creation and transfer effect，industrial chain and innovation chain synergy effect，this paper reveals the influence mechanism and action channel of China’s industrial chain and supply chain. Based on the data of UN Comtrade，we compare and analyze the changes of trade correlation between China and RCEP’s member countries and G7 countries after the signing of RCEP. Finally，it provides policy suggestions for optimizing China’s industrial chains and supply chains in terms of standardizing the high-standard economic and trade rules of RCEP，strengthening economic and trade cooperation with ASEAN countries，and promoting the integration of industrial and innovation chains among China，Japan and Korea. This chapter provides important theoretical and policy references for China to build a new system of high-level open economy and modernize its industrial chain and supply chain during the 14th Five-Year Plan period.