Objective Under the background of Sino-US trade friction, this paper analyzes the impacts of tariffs on the three margins of Sino-US bilateral aquatic product export growth, and puts forward some policy suggestions to maintain the growth of Sino-US bilateral aquatic product export.

Method The ternary marginal analysis model and VAR model were used to explore the internal mechanism of Sino-US bilateral aquatic product export growth, and the main factors affecting the growth of Sino-US bilateral aquatic product export were analyzed.

Result On the whole, in China's aquatic product exports to the United States, the quantity margin brought a contribution of 83.98%, the price margin of 41.34%, while the expansion margin produced a negative contribution of -25.32%. In the export of aquatic products from the United States to China, the quantity margin produced a contribution of 74.73%, the price margin of 13.25%, and the expansion margin of 12.01%. From the perspective of the impact of tariff, in China's aquatic product exports to the United States, the maximum impact of tariff on the expansion margin was 8.89%, the quantity margin and price margin were 1.35% and 0.06%, respectively. In the aquatic products exported from the United States to China, the impact of tariff on price margin was 23.26%, expansion margin was 11.07%, and quantity margin was 8.51%.

Conclusion It is suggested to improve the core competitiveness of products, cultivate new varieties, build international brands, actively explore the market to achieve diversification, and actively create favorable trade conditions.