How to use trade theory to analyze the reasons for the growth of China's export trade?

China can only rely on strategic trade policy, which has certain risks. Economies of scale is the theoretical hypothesis of strategic trade policy, but it has been greatly distorted in some countries and industries. In quite a few countries and industries, the existence of economies of scale is actually not the result of high efficiency and low cost in this industry, but may be the result of government monopoly, as in China. Although China has a huge domestic market and obvious economies of scale at present, there is no unified and orderly domestic market in China, which seriously hinders the economies of scale required by some industries to implement strategic trade policies. In addition, Markussen and Ven-ables (1988) and horstmann and Markussen (1986) believe that if industries enter freely, the profits from export subsidies will induce new enterprises to join, which will reduce the concentration of industries, increase the average cost of industries, and thus reduce the profit transfer effect. For China, how to set up an industry access mechanism is an important factor to ensure a certain oligopoly of the industry to ensure the existence of economies of scale, and to maintain the competitiveness of enterprises.

2. The risk of lack of micro-foundation. When implementing strategic trade policy, it needs to be carried out through certain market channels. If a country has no micro-foundation, or the domestic market is in a state of division, it will affect the implementation effect of strategic trade policy. Without the transmission mechanism of domestic market operation, there is no channel for policy implementation. At present, China is in the process of economic restructuring, the market subject, market mechanism and market system are underdeveloped, the innovation mechanism has not been effectively established, and the implementation of China's strategic trade policy lacks the promotion of enterprises and entrepreneurs.

3. Competition mode risk. Eaton and Grossman (1986) pointed out that according to the Cournot competition hypothesis of the strategic trade model, the optimal output of each manufacturer is inferred under the assumption of the output of the opponent. However, if manufacturers are competing with Bertrrad instead of Coumot, then the best policy should be export tax rather than subsidy, because export tax can make domestic manufacturers promise not to fight price wars with foreign manufacturers, so that the two manufacturers can maintain a high level. In addition, they believe that there is only one domestic enterprise in the Brand and Spencer model. If the number of domestic enterprises is greater than 1, then there will be a contradictory tendency when determining the government intervention policy. This contradiction will exist between the motive of transferring profits with export subsidies and the traditional motive of collecting export taxes to improve the terms of trade. Therefore, export subsidies are only reasonable if the number of domestic enterprises is not too large. If the two oligarchs are committed to the constant speculative variables, and the speculative variables of each manufacturer are consistent with the actual policies of their competitors, then it is impossible to transfer rents or profits to domestic companies, and the free trade policy becomes the optimal policy. 4. Risks of resource competition. Dixit and Grossman (1986) relaxed the assumption that there is only one oligopoly industry in the economy and considered the existence of multiple oligopoly industries. They studied the situation of several monopoly industries related to the supply of fixed resources, which are called "scientists". Their research shows that when domestic export industries face the same external environment and the same production capacity, subsidized manufacturers will use a large number of domestic competitive scarce resources "scientists" to subsidize one or two industries, which will transfer domestic competitive scarce resources "scientists" from other industries to subsidized industries. As a result, the export increase of subsidized industries is at the expense of the scale reduction and export contraction of other industries, which is often higher than the profit transfer effect, so free trade is still the best choice. Many industries in China have similar competition for resources. How to solve the competition of different industries for the same resource will be the key to the smooth implementation of China's strategic trade policy and whether it can benefit from the implementation.

5. Irrational risk of government behavior. The theory of government intervention also ignores the possibility of special interest groups adopting certain policies. In the process of micro-economic intervention, the government will inevitably be influenced by special interest groups, which are ready to get more benefits at any time, but the costs are borne by large decentralized groups, which cannot obtain all the information about policies. Therefore, policy intervention is often misled. Therefore, relying on political and bureaucratic coercion, rather than relying on economic means, will inevitably reduce national welfare. When the government provides subsidies to manufacturers in order to fulfill its policy commitments, there are still inherent moral hazard problems. Domestic manufacturers will find that the pursuit of subsidies is more profitable than the pursuit of production behavior, which can only increase dependence. This pursuit of subsidies is a direct pursuit of unproductive profits caused by distortion and a typical rent-seeking behavior.

6. Income distribution risk. Gruenspecht( 1988) and Neary (199 1, 1994) believe that in Brand and Spencer's model, there is an assumption that export subsidies and corporate profits are treated equally. The government does not care about the transfer payment of domestic income, but in real life, raising subsidy funds will bring distorted costs to the economy. Gruenspeeht and Neary analyzed this situation and concluded that export subsidies are reasonable only if the opportunity cost of public funds is not too high. In addition, effective government intervention will inevitably produce harmful redistribution effects. Export subsidies will help transfer income from other directions of society to the owners and employees of protected industries. Because subsidized industries are generally high-tech industries, this kind of income transfer will either be manifested in the wage increase of employed high-paid skilled workers or the extraordinary profit growth of shareholders.

7. Information risk. Qiu (1994) analyzes the risks of implementing strategic trade policies from the perspective of information asymmetry. He first assumes that the cost of foreign enterprises is well known, while domestic enterprises may have high cost or low cost. Domestic enterprises fully understand themselves, but foreign enterprises and their governments do not. The conclusion is that when information is asymmetric, if enterprises are competing, then the government tends to design a separation policy, which has the functions of signal transmission and information screening and improves social welfare. However, if enterprises compete in Bet-trand, the government will choose a unified policy to allow domestic companies to hide their information, so that the profit transfer effect will be greater. Wong( 199 1), brainerd and Marty Mott (1992) and Collie and Hviid( 1993) also made similar researches on incomplete information, from which we can draw some similar conclusions, one of which is the importance of government policies to information dependence. It is almost impossible for the government to obtain this information.

8. Risk of overseas retaliation. Colliers (199 1) pointed out that the implementation of strategic trade policies can easily cause retaliation from the other country, especially in knowledge-intensive industries. In this way, even if the policy is effective, only one party will benefit and the other party will suffer. The overall welfare level of the world has not risen, but the global welfare has been readjusted. This kind of retaliation is more likely to occur in knowledge-intensive high-tech industries, in which economies of scale related to the world market are assumed to be more meaningful by supporters of these new theories, because these industries are usually considered to be crucial.