This paper investigates the implications of the Global Plastic Treaty on China’s Marine Environmental Protection Law (MEPL), analyzing its alignment with global standards and identifying critical gaps. While the MEPL aligns with the treaty’s goals of pollution prevention and ecosystem protection, deficiencies remain in areas such as extended producer responsibility (EPR), full-lifecycle plastic governance, and comprehensive marine plastic waste management. Drawing on international best practices from the European Union, the United States, and Asia, similarly, the study proposes actionable recommendations for enhancing the MEPL. Strengthening EPR mechanisms, improving enforcement capacities, and fostering international cooperation are essential steps for achieving treaty compliance and advancing marine environmental protection. These reforms will position China as a leader in global marine governance while addressing the urgent crisis of marine plastic pollution.