Coral reef ecosystem is a special marine ecosystem with high productivity and biodiversity, which has ecological functions such as providing habitat for organisms, participating in biogeochemical cycle, protecting shore from wave and indicating water pollution degree. The outstanding feature of coral reef ecosystem is its high habitat heterogeneity. Various habitat patches provide habitat for a wide variety of swimming and benthic organisms. These reef organisms form a variety of specific functional groups through participating in various ecological processes, and jointly fulfill important ecological functions. Sea cucumber is one of the most critical members of macrobenthic fauna in the tropical coral reef ecosystem. A variety of sea cucumber species have their unique habitat preference characteristics. They play the ecological roles in improving sediment profiles, promoting mineralization of organics and nutrients regeneration through their feeding and moving activities. In recent years, for the case of over-exploitation and coral reef degradation, the global tropical sea cucumbers have been facing bio-resource depletion and species diversity loss. Therefore, it is urgent to reveal the ecological function of tropical coral reef sea cucumbers and carry out the resource protection. In this paper, the ecological research progresses of the tropical coral reef sea cucumbers around the world are reviewed. There were obvious inter-species differences and seasonal variations in preference for coral reef patches, and the food quality, substrate type and hydrodynamic conditions were the important factors affecting sea cucumber's preference of habitat patches. Through biodisturbance, sea cucumbers can change the water content, permeability, particle composition, remineralization rate, inorganic nutrient release rate and chemical gradient of pore water in the sediments of coral reef habitats, and increase the concentration of dissolved oxygen in sediments and promote the diffusion of organic matter dissolved in interstitium water into the water body. This process will further change the primary productivity of the surface sediments and the diversity of benthic animals. The feeding and defecation process can promote the growth of the corals and alleviate the damage of ocean acidification on corals. The tropical sea cucumbers also act as hosts for a variety of small animals, which contribute the essential biodiversity to the coral reef ecosystem. Further researches should focus on the variation of sea cucumber population under the pressure of artificial harvesting, the variation dynamic of the released breeding population and the competitive relationship between the breeding population and wild sea cucumber population. The influence of the released population on the benthic community of coral reef should also be studied.