There is a positive and strong correlation between import and export volume and economic growth: from the perspective of total demand, we can see the pulling effect of exports on economic growth. Economists generally believe that export is the engine of economic growth in developing countries, and export is an important factor to expand the domestic market. The continuous expansion of exports has led to the growth of related industries, and the production structure and employment structure have been adjusted and improved accordingly. Generally speaking, the production efficiency and competitiveness of export industries are called high domestic demand industries. With the continuous expansion of exports, capital and human resources continue to flow into the export industry, which promotes the redistribution of resources, improves the overall resource productivity and drives the overall economic prosperity. However, the prospect of a country's long-term economic growth should be determined by a country's long-term supply prospect, and the market demand and its constraints should be regarded as a short-term factor. The role of import in promoting economic growth is shown from the perspective of increasing supply. So in the long run, expanding imports can also promote economic growth. The main reasons are: first, imported products can fill the domestic supply gap, thus increasing private investment and consumption and upgrading the structure of the latter two. Due to the scarcity of resource supply, in the closed economic system, the industrial structure is forced to obey the "Kannikin Law" which restricts the efficiency of resource utilization, resulting in a low-level balanced industrial structure and restricting the development of the national economy. By importing scarce domestic natural resources and combining them with abundant labor resources in China, this situation will be effectively adjusted, which will inevitably lead to rapid economic development in China. Second, through import, advanced technology and management concepts can be introduced. Science and technology are the primary productive forces, and it is an inevitable choice for governments to introduce foreign advanced technologies to develop their own economies. By introducing advanced foreign technology, we can save time, learn advanced foreign management methods, reduce the risk of waste and unsuccessful development, give full play to China's advantages as a latecomer and narrow the technological gap with developed countries. We can also acquire a certain technology, because in order to realize trade, exporters have to introduce the technology, performance, characteristics and even some parameters related to trade content to importers, and export the technology unintentionally and naturally in their trade behavior. The diffusion effect brought by this technology introduction is more obvious, and it has a stronger role in promoting economic growth. Third, import intensifies domestic competition and greatly improves the production efficiency of domestic enterprises. Although the policy of increasing imports will restrict the domestic commodity market, it will strengthen competition and bring corresponding high technology, thus producing higher efficiency.