Abstract: There were 2 families, 8 genera, 13 or 14 species of seagrass in Hainan Island, mainly distributed in the coast of the bay and lagoon, and 2 families, 8 genera, 10 species, which was monitored for a long time, as Enhalus acoroides, Thalassia hemprichii, Halodule uninervis, Halophila ovalis, Cymodocea rotunda, Syringodium isoetifolium, Cymodocea serrulata, Halophila minor, Halodule pinifolia and Halophila beccarii. In recent years, due to land pollution, marine engineering, illegal fishing and extreme weather and other natural factors, the species composition, distribution area, density and biomass of seagrass have declined in Hainan Island. There was a decline trend in species composition, and seagrass beds degenerated to patches and then to sporadic distribution. In order to curb the continuous degradation of seagrass, maintain the stability of seagrass beds and promote the protection and restoration of seagrass beds in Hainan, this study suggests that the protection and restoration of seagrass beds in Hainan Island should be based on natural restoration, supplemented by artificial restoration, and long-term monitoring and assessment of restoration effect should be conducted.