["Review of International Economics, EarlyView. ", "\nABSTRACT\nThis paper investigates the impact of trade policy uncertainty (TPU) resulting from the imposition of additional tariffs on Chinese exports to the U.S. during the U.S.‐China Trade War. Using monthly trade data spanning from 2015 to 2019, we find that TPU, measured as the tariff gap, reduces export value and export quantity, and raises export price. TPU roughly accounted for approximately 76.70% of the decline in China's export value to the U.S. during the trade war. Heterogeneity analyses reveal that the effects of TPU on export value are less pronounced for products with relatively low elasticity of substitution, intermediate goods (relative to consumption goods), and products with medium skill and technology intensity. Further mechanism analysis indicates that TPU reduces China's export value to the U.S. through sunk costs, decreasing export market entries and increasing export market exits. Quality competition can partly account for the positive impact of TPU on export price. Our study shows that TPU leads to a welfare loss for U.S. consumers and importers by increasing the unit import price and reducing the variety of imported products.\n"]