Abstract: For the deviation occassionally occured in traditional anthrone-H₂SO₄ spectrophoto-metry method in determination of the polysaccharide content of Lycium barbarum, a proper measurement condition is proposed in order to improve the determination accuracy:625.0 nm of absorption wavelength; 2.00 mL of polysaccharide solution; 4.00 mL of anthrone-H₂SO₄ reagent; 10 minutes of hydrolysis and chromogenic reaction time at room temperature. The test result shows that the determination accuracy is improved by the modified method, with average recovery rate of 98.93% (R=0.835%, n=6). It also can be referrences for other kind of polysaccharides mass fraction determination.