Global foreign exchange-In the 1970s, the United States and Saudi Arabia, the world's largest oil producer, reached an "unshakable" agreement, and both sides decided to use the US dollar as the sole pricing currency for oil, which was agreed by other members of the Organization of Petroleum Exporting Countries (OPEC). Since then, the strength of the dollar has been affecting the trend of international oil prices. As the pricing currency of oil, the appreciation of the dollar means that oil is cheaper; The depreciation of the dollar means that oil is becoming more and more expensive. The dollar index is used to measure the degree of exchange rate change of the dollar against a basket of currencies, which directly reflects the relative strength of the dollar.

Since 200 1, 1, there has been a high negative correlation between international oil prices and the US dollar index, but this relationship is not a simple reverse relationship, but a subtle one. This is because of this subtle relationship, so the dollar index usually plays a guiding role in the trend of international oil prices, but this guiding relationship is sometimes mutually transformed.