It is very important to the ecosystem of grass Because the grass is as a manufacturer. Kindergarten is also a source of aquatic animals and source of sanctuary. From the study of marine band Indo-Pacific found seagrass species Halodule pinifolia.May be at risk to endangered. So in this study Aims to study the genetic variation of seagrass species. The samples of seagrass H.Pinifolia all 7 samples from Rock Garden Beach Resort. Population, and watch the sun 5 village of 2 samples were extracted DNA method CTAB method, then use the technique Sequence-related Amplified Polymorphism (SRAP).Using a primer to check all 12 pairs. DNA bands were found all 53 DNA bands appear as monomorphic bands DNA bands were amplified 22 แถบดี was average at 1.83 DNA bands per primer pairs and polymorphic bands 31 DNA bands were mean in 2.58 แถบดี amplified per primer pairs. The genetic variation was found in 58 average.49 percent, which can be said that the genetic variation occurs. As a result of adaptation to the environment for the survival of sea grass