Abstract: Abstract：Logical analysis shows that the friction between China and the United States in the fields of trade, finance, investment, science and technology is bound to cause the uncertainty of China′s “passive follow-up” trade and other policies, and the cyclical nature of the friction will be normalized and long-term,which will have a significant impact on the transformation and upgrading of China′s foreign trade industry.In this regard, by measuring the trade policy uncertainty index and the foreign trade transformation and upgrading index in 2007-2017 of China and the United States, this paper constructs an inter provincial panel data model to test the mechanism of trade policy uncertainty on China′s foreign trade transformation and upgrading.The results of full sample regression show that the improvement of trade policy uncertainty will inhibit the process of China′s foreign trade transformation and upgrading. The results of regional sample regression show that the impact of trade policy uncertainty on China′s foreign trade transformation and upgrading in different regions is different in degree and time.According to the above conclusions, the government and enterprises should dynamically deal with the relationship between the uncertainty of trade policy and the transformation and upgrading of foreign trade industry, implement the differentiated regional policy system, and fully consider the political and economic factors of trade partner countries, so as to avoid the inhibition of trade policy uncertainty on the upgrading of foreign trade industry.

Key words: Sino-U.S. trade friction, trade policy, uncertainty, foreign trade transformation and upgrading, evaluation index