The paper discusses the study of biogeomorphology in mangrove coast, including The research objectives, the main research contents and the research methods. The research objectives are identifying the geomorphic function of ecosystem of mangrove coast ,elucidating the process of changes of mangrove coast ,forecasting the response to global changes and human activities and providing bases for the management of mangrove coast zone. The main research contents are biogeomorphology function of mangrove ecosystem,the response of biogeomorphology of mangrove coast to global changes ,the process of changes of mangrove coast since the late Quaternary , the model constructing of the system of mangrove coast and the forecasting of the changes of mangrove coast. The research methods are carrying out the long term and short term field measures ,combining the cross research in different subjects with several kinds of observational methods and emphasizing the modal research.