If an economy often runs a trade deficit, national income will flow abroad, thus weakening the national economic performance. If the government wants to improve this situation, it must devalue its own currency, because devaluation, that is, lowering the price of export commodities in disguise, can improve the competitiveness of export products. Therefore, when the country's foreign trade deficit expands, it will weaken the country's currency and make it fall; On the contrary, when there is a foreign trade surplus, it is good for this currency. Therefore, the international trade situation is a very important factor affecting the foreign exchange rate. It can be seen from the influence of an economy's foreign trade on the exchange rate that the balance of payments directly affects the change of a country's exchange rate. If there is a surplus in a country's balance of payments, the country's demand for money will increase, and the foreign exchange flowing into the country will increase, which will lead to an increase in the currency exchange rate. On the contrary, if a country has a deficit in its balance of payments, the demand for its currency will decrease, and the foreign exchange flowing into the country will decrease, which will lead to the decline of its currency exchange rate and the depreciation of its local currency. Specifically, in the balance of payments, in addition to the above-mentioned trade items, there are also capital items that have the greatest impact on exchange rate changes. The surplus or deficit of trade balance directly affects the rise or fall of currency exchange rate.