Abstract: Chinese merganser (Mergus squamatus) is an endangered species with a long history. The progress in the research of Chinese merganser was systematically expounded in this review. The results showed that (1) For the population distribution: Russian Far East carried the main body of Chinese merganser breeding population, while China carried the main body of the wintering population. (2) For habitat selection: forest elements, water characteristics and concealment were the three factors determining habitat selection for Chinese merganser. (3) Behavior: behavior habits were mainly driven by temperature, sex ratio, and grouping characteristics. (4) Breeding ecology: nesting condition was one of the important factors limiting population breeding. (5) Endangered mechanism: the threatening factors included genetic diversity, self-habits and interspecific stress, and human activities were the main threat factor. (6) Conservation strategy: the habitat should be optimized according to the species’ habits and the conservation network should be constructed. Overall, current research mainly focused on ecology and related fields, forming the basic cognition of Chinese merganser. However, many conclusions were contradictory or generally speculative. Further research should be carried out from fidelity of wintering land, water area characteristics, and mating time. New technologies and ideas should be applied to deepen the understanding of Chinese merganser with multidisciplinary combination, so as to promote the effective protection of this rare species.

Key words: Mergus squamatus, water characteristics, nesting condition, endangered mechanism, species protection.