Ecosystem health is a new research topic in the field of ecology and environment science. Firstly, based on the understanding and analysis of a lots of literature both at  home and abroad, this article entirely summarizes the evolvement of the concept of health from mankind to ecosystem and aims at  obtaining the assessment criteria of ecosystem health. Then, the article proposes the concept and applicaiton of three kinds of main research methods about ecosystem health assessment:① indicator species, ② indicator system, and ③ indicator area. Finally, this article provides some focus challenging and controversial topics of ecosystem health and the major issues which need further discussion in the future.