In this paper, a brief introduction was made to the position of mangroves in coastal wetlands, mangrove species and their distribution, the definition of mangroves, importance of mangrove protection, and the social, economic and ecological values of mangroves. The 4 aspects of ecological engineering questions to be faced with were emphasized. They included： 1) The key to the mangrove rehabilitation is the choosing standard for the land fitting for afforestation; 2) The ecological models of sea beach building in mangrove areas; 3) Prevention of ecological invasion; and 4) Smallest resource and environment cost for largest social and economic benefits from mangroves.