The so-called trade surplus means that in a specific unit time (usually calculated on an annual basis), a country's total export trade is greater than its total import trade, also known as "surplus", which means that the country's foreign trade in that year is in a favorable position. The size of the trade surplus largely reflects a country's foreign trade activities in a specific year.

Under normal circumstances, a country should not have a large foreign trade surplus for a long time, because it is easy to cause friction with relevant trading partners. For example, one of the main reasons for the fluctuation of bilateral relations between the United States and Japan is that Japan has long been in a state of huge surplus.

A large amount of foreign exchange surplus usually leads to the increase of local currency in a country's market, which is easy to bring inflationary pressure and is not conducive to the sustained and healthy development of the national economy.

The essence of huge trade surplus is the result of excessive export, which will bring long-term harm to the economy and people's living standards. In the past, China's trade surplus was very large, with raw materials and basic daily necessities as the main export commodities, and few high-tech and high value-added commodities. In particular, it is an "extensive" mode of economic growth to obtain foreign exchange by exchanging cheap clothing industry for aircraft trade. We continuously send cheap and good daily necessities to developed countries, so that they can enjoy better products than their own at low prices, but what we get is excessive foreign exchange reserves.

Summary: Excessive trade surplus is a dangerous thing, which means that the growth of domestic economy is too dependent on external demand and the dependence on foreign countries is too high; The huge trade surplus has also brought about the expansion of foreign exchange reserves, which has brought greater appreciation pressure to the RMB, and also given the international trade protectionist forces an excuse to reflect the undervaluation of the RMB with a huge trade surplus, which has increased the pressure of RMB appreciation and financial risks, and increased the cost and difficulty of RMB exchange rate mechanism reform. In this regard, the relatively simple countermeasures are to change the "extensive" economic growth mode, reduce the trade surplus and stimulate domestic consumption.