Many coral reefs around the world were damaged during the 1998 mass bleaching event. The acroporids in the lagoon of Dongsha Atoll were eliminated during massive bleaching, and they are still not recovered. Three hypotheses were proposed to explain how the lagoon of Dongsha Atoll has not recovered during the past twelve years¡G1. the lack of recruitment, 2. the persistent interfering on newly recruiting acroporids by hot water, 3.the interfering on those acroporids by predators. Four types of habitats, i.e., reef tops, reef slopes, reef bases, and inter-patch-reefs were surveyed on their coral communities, densities of juvenile corals, growth rates, pests and diseases of corals. The tissue samples were collected to assess reproductive status of corals. Moreover, Acropora muricata branches were transplanted from north coast of Dongsha Island to 3 m and 9 m depths in the lagoon of Dongsha Atoll for testing suitability of the environment. The acroporids were mature, and they spawned between March and May in 2010. Live coral coverage was 16% on average; small coral densities were 1.5/m2, much lower than other lagoons. Besides, acroporid represented 8% of coral coverage and 4% of juvenile corals which are lower than those of other lagoon. Water temperatures were higher in 2010 than 2009. However, coral skeletal extension rates do not show any reign of reduction. In addition, most acroporids survived 2010 summer¡]sea water temperature exceeded 30¢J¡G40-64%¡^ in the transplantation experiment. During two years of survey, only 6 individuals Acanthaster planci. So the lack of recruits might be the bottleneck to the recovery of acroporid in Dongsha lagoon.