Abstract: Morphology, physiology, biochemical composition and growth of Spirulina siibsalsa were studied and compared with those of other Spirulina. There are no apparent differences in protein content, amino acid composition and contents of several pigments among S. subsalsa, S. maxima and S. platensis. The generation time of S. subsaha is 8.4 hours. This growth rate is higher than that of any other species reported in the present paper. The generation times of 5. maxima, S. platensis 1926 and S. platensis 2340 are 11.0, 11.8 and 14.8 hours respectively. S. subsalsa exhibits a wider tolerance of temperature and salinity, and is easily harvested with simple methods. Both rates of photosynthetic oxygen evolution and respiratory oxygen uptake of S. subsalsa are higher than those of S. maxima and S. platensis. The potential of improving the medium is discussed.