1, the yield of US Treasury bonds is high, and the exchange rate of the US dollar will be high.

Many investment institutions and investors hold government foreign exchange reserves and dollar assets in the form of US Treasury bonds. If the yield of US Treasury bonds is higher, it means that it is more attractive to investors, and investors will pursue the US dollar and exchange their funds for US Treasury bonds, then the exchange rate of the US dollar in the foreign exchange market will rise.

2. In the European debt crisis, some high prices raised the yield of government bonds and non-American currencies fell.

The emergence of the European debt crisis is because some countries have high debts and are unable to repay them. Before the American financial crisis, some European countries could maintain their fiscal expenditure by issuing new debts and repaying old debts. However, after the financial crisis, investors in the whole international financial market lost confidence, no one bought new bonds issued by these countries, and the old national debt market kept selling. As a result, the principal and interest of the national debt cannot be paid, the national sovereign debt loses credibility, and the national sovereign credit rating is downgraded. Investors' willingness to invest is weak, and even if the interest rate on bonds is raised, it will not restore investors' confidence. Therefore, the interest rate on government bonds is raised and the non-US currencies are still lower.