In recent years, with the formal implementation of the Regional Comprehensive Economic Partnership (RCEP) and the rise of the blue economy, the trade cooperation between China and ASEAN in aquatic products has been further deepened and expanded. This paper utilizes United Nations Commodity Trade (UN Comtrade) data from 2001 to 2023 and combines the perspective of the blue economy to systematically analyze the characteristics of bilateral trade volume, growth rate, market distribution, and trade types of aquatic products between China and ASEAN. By applying the modified Constant Market Share (CMS) model, the paper conducts a factor decomposition and effect analysis of the growth factors in China’s aquatic exports to ASEAN. The analysis indicates that the competitiveness effect has the highest contribution rate, and competitiveness has been the primary driver of growth in China’s aquatic product export trade to ASEAN, followed by the growth effect increasing year by year, which shows the impact of the scale of demand, while the product effect is relatively low. In particular, product structure urgently needs improvement to meet the requirements of the blue economy. In ASEAN’s aquatic product exports to China, demand scale serves as the main driving force, with the product variety adapting to the Chinese market as a secondary contributor. However, under the blue economy framework, product sustainability and environmental friendliness have emerged as new considerations, while the contribution of competitiveness remains relatively low, suggesting a need for further enhancement to align with green trade standards.