Wetland health assessment is an important part of wetland science characterized by complex context and various assessment methods. There are different methods to meet different assessment goals. The researchers in USA have done much work on wetland health assessment over the past decade, and this paper mainly introduced three level assessments developed and applied in USA including as level Ⅰ, level Ⅱ and level Ⅲ. The application scope, the advantage and disadvantage and the assessment steps were described in the paper, for purpose of offering reference for wetland ecologic health assessment in China.