Abstract: Based on the flight condition tests of UAV flight parameters, flight height, tidal level and survey field, the UAV was used to take aerial photos of seagrass on the coastal sea area of Dongjiao Coconut Forest, and the PIX4D software was applied to obtain the high-resolution image of seagrass distribution. The ArcGIS software was used to extract the vector distribution area of the seagrass bed. The distribution characteristics and seagrass species in the test area were obtained. The results show that seagrass distributes on coral reef within 300 m offshore patchily and separately, and the distribution area of seagrass is 2 449.6 m², accounting for 24.5% of the total test area. According to the field survey, there are five species of seagrass: Cymodocea rotundata, Halodule uninervis, Enhalus acoroides, Thalassia hemprichii and Halophila Ovalis. Among them Thalassia hemprichii is the dominant species. Halodule uninervis and Halophila ovalis mainly distribute in the low tide silty area of intertidal zone. Cymodocea rotundata distributes from the low tide zone to the upper part of the subtidal zone at the junction of seabed accumulation and scouring area. Thalassia hemprichii distributes in different water depths occupying the largest area of seagrass bed.