High foreign exchange reserves are often caused by the undervaluation of the local currency. This is unfair in international trade, because the local currency is undervalued, and the export price measured by foreign currency is lower, which has a price advantage; Therefore, competitors and importers often ask exporters to appreciate their currencies. To a certain extent, the higher the foreign exchange reserves, the greater the degree to which the local currency is undervalued. But the higher the foreign exchange reserves of countries, the higher the ratio will be, such as oil exporting countries.