The marine economy has become an increasingly important contributor to the global economy due to advancements in science and technology and humans’ growing ability to manipulate nature. As a country with a vast marine territory, China has the important responsibility of utilizing marine resources rationally and promoting sustainable development of the marine economy. Since the introduction of the Marine Environmental Protection Law of the People’s Republic of China (MEPL) in 1982, China has made significant progress in strengthening the legal framework for marine environmental protection. MEPL has undergone several revisions to improve its legal content under the guidance of national policies. On October 24, 2023, the Standing Committee of the National People’s Congress revised and adopted MEPL again. This paper analyzes the changes in the contents of the new law and the legal background at home and abroad while integrating the domestic and international legal backgrounds. This paper provides an in-depth analysis of the changes made in the new law, summarizes the revision ideas, and examines the new law in the context of domestic and international laws. The aim is to provide a clear understanding of the spirit and purpose of the legislation.