Abstract: A new strain of Spirulina sp. was separated from sewage, and the suitable medium was selected. This Spirulina sp. was as long as 1750 μm, it waves and rotates actively under optimal living conditions. The water in which this Spirulina sp. lived was slightly acid or hypereutrophic, the salinity was low,and the temperature was 5³4℃,the concentration of total nitrogen and total phosphate were 4.53⁴.96 mg/L and 0.39⁰.48 mg/L respectively. Culture experiments revealed it grew only under low light intensity, which is quite different from the Spirulina’s common characteristics of adaptation to high light intensity, high temperature, high salinity and high alkaline. NH⁺₄ is helpful for this Spirulina sp. to grow. The Spirulina sp. adapted well to sewage, thus it may be applied in purification of sewage.