Abstract: The single factor and orthogonal experiments were performed to optimize the cultivating conditions of Dunaliella sp. which was collected from salt lake in Yuncheng, Shanxi, China. Temperature, Na Cl, N, P and Fe were studied for effects on β-carotene contents of Dunaliella sp. The results showed that there was a good linear relationship between β-carotene contents of Dunaliella sp. and OD453 nm. The β-carotene contents of Dunaliella sp. was measured by the method of optical density which was simple, accurate and efficient.Dunaliella sp. was cultured under 20~25℃ and 1.0~2.0mol/L (Na Cl) that were conducive to the β-carotene accumulation. When Dunaliella sp. cells grow to the logarithmic phase, high concentrations of N and P were not conducive to the accumulation of β-carotene, and the concentration of Fe had no effect on the accumulation ofβ-carotene. The optimum concentrations of Na NO3, KH2PO4 and Fe C6H5O7 for β-carotene accumulation were0.6200, 0.0256, 0.0010g/L. The medium for β-carotene accumulation of Dunaliella sp. was optimized for lay the theoretical foundation of future development and utilization of local high β-carotene production algae strains.