Abstract: Based on the survey in seagrass beds along the coast of Wenchang, Hainan Province in 2012, 2018 and 2020, we compared the growth status and recessions， and analyzed the influencing factors leading to the seagrass bed recessions. The results showed that there were 6 species of seagrass belonging to 6 genus in 2 families along Wenchang coast, including Thalassia hemprichii, Cymodocea rotunda,Halodule uninervis, Enhalus acoroides, Halophila ovalis and Syringodium isoetifolium. The seagrass beds along Wenchang coast experienced significant degradation, with area decreased from 31.8 km² in 2012 to 24.2 km² in 2018, and to 18.8 km² in 2020. Similarly, the number of species, coverage, density and biomass of the seagrass also declined from 2012 to 2020. Statistical analysis showed that contents of heavy metal ions such as Cu, Cd and Cr are significantly negatively correlated with the seagrass coverage, indicating that the heavy metal pollution from aquaculture effluent around seagrass beds may be the main reason for the deterioration of seagrass beds.