Abstract: Taking Agaricus blazei mycelium FJWZY-1 as the starting strain and its biomass as the evaluation index, three main factors affecting fermentation-pH, rotation speed, and carbon-to-nitrogen ratio were studied. Based on single-factor experiments, a three-factor, three-level response surface optimization experiment was designed to determine the fermentation conditions for Agaricus blazei mycelium. The results showed that: the data from single-factor experiments indicated that the optimal pH, shaker oscillation speed, and carbon-to-nitrogen ratio（C/N ratio）of the medium for the fermentation of Agaricus blazei mycelium FJWZY-1 were 6.0, 100 r·min⁻¹, and 10∶1, respectively, with the biomass of Agaricus blazei mycelium FJWZY-1 was 6.6 g·L⁻¹. On this basis, the response surface methodology（RSM）was employed to optimize the fermentation process. The results demonstrated that the optimal fermentation conditions were consistent with those from the single-factor experiment, and the order of the influencing power of different factors was as follows: carbon-to-nitrogen ratio（C/N ratio）of the medium ＞ pH ＞ shaker oscillation speed. This study lays a foundation for achieving the rapid growth of Agaricus blazei mycelium, increasing its biomass, further extracting Agaricus blazei polysaccharides, and realizing its large-scale fermentation production and cultivation.