The International Monetary System (IMS) touches on the most fundamental problem surrounding the international monetary, financial relationships, including the international system of foreign exchanges, international system of payment and settlement, international coordination of payments, international solvency supply, international financial institutions, etc., and the consequent institutional arrangements. The IMS represents an important aspect of the modern international economic relation. It not only plays a major role on the exchange rate system, foreign exchange policy, the management of reserve assets of each nation, but also has a profound impact on the worldwide formation of trade patterns and economic development. Chronologically, the development of the IMS can be divided into three stages: the stage of the international gold standard, the period of Bretton Woods System, and the current time of Jamaica System. This chapter first looks at the concepts and main contents of the International Monetary System, and then along the line of history analyzes the evolution of the IMS, while exploring the improvement of the IMS, the current state of the European monetary system, and introducing the reader to the background on which the IMS is established, and the mission and business activities of the IMS. At the end, we investigate the systemic three-ringed structure of viable, independent economic systems.