As an important part of the wetlands, isolated wetland's role is growing up in human society. The research of the definition "isolated wetland" was conducted abroad earlier, The CROPS considered it to be those that are not adjacent to navigable water or not connected via surface water. However, China only put forward some related concepts, such as "Annular Wetlands", "Dish-Like Depression", "Fragmentation of Wetland Landscape" and so on. There is little research on the tpye and theory of the isolated wetland at home and abroad, at the same time, it doesn't form a complete theoretical system, the researchers only proposed some characteristics, such as isolation, hydrology connectivity, biological connectivity, etc. The function research is the focus of the isolated wetland research, this paper briefly expounds the climate function, hydrology and water quality function, habitat function, etc. For the protection of isolated wetlands, foreign countries have formulated definite laws and the corresponding measures, but our country need improvement in this aspect. Through introducing the definition, tpye, characteristic, function and protection of isolated wetland, this paper discusses the potential trend of hot issue and direction in future research.