Tuna products are among the most popular seafoods in the world and widely traded across the globe. China is a major contributor to the worldwide tuna industry as both a producer and an exporter. Employing the Constant Market Share model, this study examines the factors influencing the variations in China’s tuna exports from 2002 to 2022, focusing on global, country, and product type levels. Results show that (1) China’s expanded tuna exporting trade is partially due to the rising worldwide demand for tuna, which is mostly prominent in China’s tuna exports to the USA, Vietnam, and Malaysia, as well as its exports of frozen tuna products. (2) China’s competitive edge in tuna exports has steadily strengthened in most of its principal exporting markets, especially in Japan and the fresh tuna markets. Nevertheless, the competitiveness structure of Chinese tuna exports has challenges in satisfying the diverse requirements of different nations (regions) for various types of tuna products. (3) The second-order effect has been the primary driver of the expansion in Chinese tuna exports, with its contribution rate consistently rising in recent years. In response to the changes in international and domestic tuna markets, China must implement strategies to maximize the potential of the tuna importing market, further improve its global competitiveness, enhance communication and coordination among domestic and international tuna stakeholders, and cultivate domestic tuna markets.