The Impact of High-Quality Development of Foreign Trade on Marine Economic Quality: Empirical Evidence from Coastal Provinces and Cities in China

Against the backdrop of a complex global economic landscape, foreign trade serves as a critical link integrating China’s marine economy with the global market, playing an indispensable role in advancing high-quality marine economic development in China and realizing the strategic goal of building a strong maritime nation. Utilizing panel data covering 11 coastal provinces and municipalities in China from 2013 to 2022, this research adopts a double machine learning approach to examine the effects and mechanisms through which the high-quality development of foreign trade (HQD) shapes high-quality marine economic development (THQ) in China. The empirical results demonstrate that (1) high-quality development of foreign trade significantly promotes high-quality marine economic development in China, with a 1-unit increase in the former corresponding to a 1.437-unit rise in the latter. This finding withstands multiple robustness checks. (2) Mechanism analysis indicates that this promotion occurs through three channels: strengthening marine environmental regulation, enhancing marine labor productivity, and upgrading the marine industrial structure. (3) Heterogeneity analysis shows that the effect of high-quality foreign trade is stronger in China’s eastern marine economic region. Simultaneously, the trade development environment emerges as a key factor exerting a significantly positive influence on marine economic quality during China’s foreign trade advancement. The empirical findings propose the following optimization countermeasures for high-quality marine economic development: strengthening marine environmental regulation, enhancing marine labor productivity, and promoting the upgrading of the marine industrial structure.