Abstract: In this article we reviewed and discussed the research advances on the marine higher plant eelgrass (Zostera marinaL.) from 5 aspects including (1) characteristics of morphology and anatomical structure， (2) basic physiology， (3)salt_tolerance mechanism， (4) possible growth_limiting factors， (5) questions and expectations. Special emphasis was put on the plant's suitability with its submerged life in seawater, especially its adaptation to the salinity of seawater.