Qiongzhou Strait is the waterway between Hainan island and Leizhou peninsula, and it is one of the three great straits of China with rich Marine species there. To research on the Community structure characteristics of crab species in Qiongzhou Strait, based on the data of 22 positions acquired from marine resources surveys conducted in May and October of 2016 using bottom trawls, the community structural characteristics were analyzed such as species composition, dominant species, and diversity of crab, and the similarity and dissimilarity of community structures were quantitatively analyzed. The result shows that, a total of 31 species have been identified through the survey, which belong to 19 genera in 12 families, the dominant species is Parapenaeopsis hardwickii; the crabs living in areas no deeper than 20m are the largest in terms of species number which decreases with the increase of water depth. In autumn, the richness index (D) is 0.46, evenness index () is 0.65 and diversity index () is 1.07, which are all higher than in spring. The research shows that, Parapenaeopsis hardwickii exerts great influence on the spring community structure, while Portunus pelagicus, Matuta planipes, Charybdis japonica, Charybdis feriatus, Portunus trituberculatus and Lauridromia dehaani have great influence on the autumn community structure.