1944, Britain and the United States reached an understanding after a heated debate. In May of that year, the United States invited representatives of 44 governments involved in the preparation of the United Nations to hold a meeting in Bretton Woods, signed the Bretton Woods Agreement, and established the second international monetary system after the collapse of the gold standard-the Bretton Woods system. The core of this system is the "double peg" system, that is, the dollar is linked to gold, and the currencies of various countries are linked to the dollar. The dollar is at the center and plays the role of the world currency, while the United States undertakes the obligation to exchange official prices for gold. In fact, it is a new gold exchange standard system. In the Bretton Woods monetary system, the role of gold in circulation and international reserves has decreased, and the dollar has become the protagonist in this system. However, because gold is the last barrier to stabilize this monetary system, the price and flow direction of gold are still strictly controlled, and residents are prohibited from buying and selling gold freely in various countries, so it is difficult for the market mechanism to play an effective role.

Whether the Bretton Woods monetary system can run smoothly is closely related to the credibility and status of the US dollar. In the 1960s and 1970s, the United States was mired in the Vietnam War, with a huge fiscal deficit and deteriorating international income. The credibility of the US dollar was greatly impacted, and several US dollar crises broke out. A large amount of capital fled, and countries sold dollars and snapped up gold, which greatly reduced the US gold reserves and led to the skyrocketing price of gold in London.

In the late 1960s, the United States further expanded its war of aggression against Vietnam, the balance of payments further deteriorated, and the dollar crisis broke out again. The United States is no longer able to maintain the official price of gold. After consulting with members of Jinchi, it announced that it would no longer supply gold to the market at the official price of $35 per ounce. The market price of gold fluctuates freely, but governments or central banks of various countries still settle accounts at the official price, thus beginning the stage of the dual price system of gold where the market price and the official price coexist. But the dual price system only lasted for three years. European countries have adopted the strategy of "please enter the urn". Because the United States refused to raise the price of gold and the depreciation of the dollar, they exchanged dollars for American gold reserves.

When it was reported in August 197 1 that France and other western European countries were preparing to exchange dollars for gold in large quantities, the United States had to announce in August 197 1 that it would stop fulfilling its obligations to foreign governments or central banks and exchange dollars for gold for the United States. 197 1 year 12 marked by the Smithsonian agreement, the dollar depreciated against gold, and the Federal Reserve refused to sell gold to foreign central banks. At this point, the system of linking the dollar to gold exists in name only. The depreciation of the US dollar in March 1973 once again triggered a wave of selling US dollars and snapping up gold in Europe. The foreign exchange markets in western Europe and Japan had to be closed for 17 days. After consultation, an agreement was finally reached, and western countries abandoned the fixed exchange rate system and implemented the floating exchange rate system. At this point, the Bretton Woods monetary system completely collapsed.

After the collapse of Bretton Woods system, the floating exchange rate system replaced the fixed exchange rate system. Since then, the foreign exchange trading of the Fortune Global Gold Exchange has entered the market-oriented stage, and then the foreign exchange market has developed into the largest and most active financial market in the world, and it is also the most liquid market in the world today. The dollar is the strongest currency among all currencies today. The most important foreign exchange in foreign exchange reserves of various countries is the US dollar. In the international market, most goods are priced in dollars. Therefore, the trend and rise and fall of the dollar are the most concerned things for all traders. At this time, we need an index that reflects the overall strength of the US dollar in the foreign exchange market, that is, the US dollar index.

The dollar index is not from the Chicago Board of Trade (CBOT) or the Chicago Mercantile Exchange, but from the new york Cotton Exchange (NYCE). New york Cotton Exchange was founded in 1870, which was originally composed of a group of cotton merchants and middlemen. It is the oldest commodity exchange in new york and the most important cotton futures and options exchange in the world. 1985, new york cotton exchange established the finance department, and officially entered the global financial commodity market. The first is the US dollar index futures. 1986, launched the dollar index futures option. Although it appeared 13 years later than foreign exchange futures, because it catered to the market demand, the US dollar index became an important economic indicator of great concern to market participants, and it was successful.