The objective of this study was to improve the yield of polysaccharide from Spirulina sp. by alkaline extraction (NaOH) 0.1, 0.3 and 0.5 N at 40, 60 and 80^oC for 1, 2 and 4 hrs.  The result showed that alkaline concentration and extraction temperature had significant impact on the yield of polysaccharide. The yield of polysaccharide extraction of amount 8.29 % of dry weight was obtained under the optimized condition: alkaline concentration at 0.1 N, extraction temperature at 80 ^oC and extraction time for 4 h. The monosaccharide from polysaccharide extracted contained glucose, galactose, and arabinose.