Abstract: In order to improve the polysaccharide production of Cordyceps gunnii, the optimization of the nutritional conditions of the liquid fermentation was carried out. With the production of intracellular polysaccharide (IPS) which was shaking cultivated in triangular bottles as optimization indexes to select carbon source types, nitrogen source types and add quantity of them. Results of carbon source single factor experimental showed that the best carbon source was sucrose, and when the adding amount was 4% , the yield of IPS up to 147.40mg/100mL. Results of nitrogen source single factor experimental showed that the best nitrogen source was peptone, and when the adding amount was 1.0% , the yield of IPS up to 102.49mg/100mL. The results of the orthogonal test indicated that the optimum nutritional condition was sucrose 4% , peptone 1.0% , KH₂PO₄ 0.05% and MgSO₄ ·7H2O 0.1%. Under this condition, the polysaccharide production reached (181.5±2.3) mg/ 100mL.