Abstract: Sanghuangporus vaninii,a large-scale medicinal fungus, has a shortage of resources due to its long growth period and unreasonable development, and a large amount of mycelium can be obtained in a short time through liquid fermentation culture.In this experiment, the mycelial biomass was used as the main index to optimize the liquid medium of Sanghuangporus vaninii.Screening of carbon source, nitrogen source and inorganic salt in liquid medium of Sanghuangporus vaninii by response surface methodology.The results showed that the best carbon source of poplar mulberry was glucose.The best inorganic salt was MgSO₄·7 H₂O,the most suitable medium formula was glucose 34.44 g·L^-1,peptone 7.26 g·L^-1,yeast extract 8.303 g·L^-1,MgSO₄·7 H₂O 2.618 g·L^-1 and natural pH,at this condition, the biomass yield of Sanghuangporus vaninii was the highest at 2.733 05 g, which was basically consistent with the predicted value.It is concluded that the optimized liquid medium can significantly improve Sanghuangporus vaninii mycelial biomass.