Abstract: This paper systematically studies the composition of polysaccharides and monosaccharides in four species of blueberries (fresh fruit), i. e. Northland, Bluecrop, Patriot and Duke. The monosaccharides were extracted by ethanol solution and polysaccharides via purified water. Spectrophotometry and GC pre- column derivatization were used to study the composition of polysaccharides and monosaccharides on the above four species of blueberries (fresh fruit). The results indicated that the total amount of free monosaccharides were between 24.18 and 33.18 mg/ g, while Bluecrop had the highest amount of free monosaccharides. The predominant three free monosaccharides were fructose, glucose and galactose. And the content of fructose accounted for 93% among all free monosaccharides. As with polysaccharides, the total amount of them were between 3.54 and 5.87 mg/ g (fresh fruit), while the patriot had the highest amount. Also the study showed that polysaccharides from four different species of blueberries were all contain erythrose, arabinose, rhamnose, fucose, xylose, fructose, galactose and glucose, and the predominant three were fructose, glucose and galactose.