The healthy marine ecological environment is an important guarantee for the human to exploit and utilize marine resources sustainably. The comprehensive assessment of the health of the offshore marine ecological environment can provide a scientific basis for the benign development of marine ecological environment and social and economic decision-making. In this paper, we firstly compared three representative methods of the comprehensive assessment of marine environmental health in the world, including the Ocean Health Index (OHI) by Conservation International (CI) and National Center for Ecological Analysis and Synthesis (NCEAS), the National Coastal Assessment methods by U.S. Environmental Protection Agency (EPA), and Comprehensive Assessment Method of Ecological Status by European Union. These three methods all belong to comprehensive index system methods, but present significant differences in selection and weight of indicators, as well as in the final rating. Then, we summarized the research progresses in the field of marine ecological environmental health assessment in China. In recent ten years, the research on marine environmental health assessment in China is increasing. Although the assessment frameworks used were various, most of them referred to national standard documents. Based on the research status at home and abroad, we built a dual-core assessment framework using the comprehensive index system method under the principle of scientific nature and operability. In this framework, the inner core assessment was mainly about the status of marine ecosystem, while the outer core assessment mainly reflected the contribution of the ocean to the human economy and society. For the inner core elements, 13 indicators in total were selected, each representing one specific aspect of marine environment health. For the outer core elements, 4 indicators were selected to reflect the utilization status of ocean resources by human society. For the convenience of calculation and comparison, the scores of all indicators were normalized to 0-1. The core essence of our framework is that the development and utilization of marine resources by human society must base on the health of marine ecological environment. Therefore, the final assessment result was kept in two parts, the grade of inner core elements and the score of outer core element, which could provide clear guidance for management decision-making. We hope that this assessment framework will be able to assess the health status of China's offshore marine environment scientifically, accurately and comprehensively.