Agar is a valuable polysaccharide which has widespread uses in different industries. Biologic and biotechnological uses of agar are being improved day by day. Red algae especially members of Gracilariaceae are main resources for the extraction of the polysaccharide. Recognition of the family species and study on morphology and biological features of them are very important for economic exploitation. Gracilaria salicornia (C. Agardh) Dawson (Gracilariaceae, Rhodophyta) is a member of the agarophyte algae in the Qeshm island in the south of Iran (Persian Gulf). In this research, morphological and biological features of the species communities on intertidal regions of the southeast coastlines of the island were determined biological and morphological differences of the species at different intertidal levels. The results showed the quality and quantity of the species growth in the communities of the species which are located in lower parts of the intertidal regions are higher than the upper parts. Depth of the water is important as effectual environmental factors on both quality and quantity of the species growth.