Abstract: Dunaliella salina is known as probably the most halotolerant eukaryotic organism living in various salt habitats, and glycerol metabolism plays an important role in its osmoregulation. We investigated the growth, intracellular glycerol content and activities of enzymes in glycerol metabolism under NaCl stress. Growth of D. salina was inhibited in solutions containing 4.0, 3.0, 0.8, and 0.6 mol.L-1 NaCl. The intracellular glycerol content accumulated and activities of glycerol 3-phosphate phosphatase and dihydroxyacetone reductase catalyzing dihydroxyacetone to glycerol were enhanced in response to hyperosmotic stress. However, glycerol content decreased and the activities of glycerol 3-phosphate phosphatase lost and dihydroxyacetone reductase catalyzing glycerol to dihydroxyacetone increased when adapting to hypo-osmotic stress. The paper discusses the association of glycerol metabolism with the osmoregulation mechanism of D. salina.