International trade efficiency is an important index to reflect the international competitiveness and the potential of international trade cooperation of a country. It is an important reference for selecting the target countries of international trade. In the long run, a country can only maintain the efficiency of trade for a long time, and constantly improve the vitality of international exchanges, has it always maintained an advantage in the fierce competition of international market. And this advantage has the national property, the other countries can't replace it. From this perspective, the promotion of national trade efficiency will not only enhance the competitiveness of the international market, but also provide an important reference for the selection of a good partnership with other countries.The propose of "the Belt and Road" national strategy makes China linked with the world more closely. In order to the further promotion of the world economy towards a healthy, stable and sustainable development, we must thoroughly study the trade efficiency of all countries in the world, especially based on the investigation of Chongqing. We must investigate the trade efficiency in key countries along "YU-XIN-OU",positively use research results to provide support for the further promotion of our "the Belt and Road" strategy.Based on the above reasons,the evaluation on the trade efficiency in key countries along "YU-XIN-OU" has attracted more and more great attention from theoretical, academic circles and national strategic decision makers. <<