To explore the safety of different doses of Cordyceps militaris solid fermentation (SSF product) and its effects on intestinal health and immunomodulatory function of normal mice， and to evaluate the potential effects of SSF product on body health. The content of solid fermentation products of Cordyceps militariswas analyzed by HPLC. The mice were randomly divided into four groups: control group， SSF product low， middle and high dose [35， 70， 210 mg/(kg·d)] group. After 4 weeks of feeding， the weight of organs， the proliferation and transformation ability of spleen lymphocytes and the level of cytokines in serum were measured. The changes of intestinal flora were detected by high-throughput sequencing. The results showed that compared with fruiting body， the contents of protein， crude polysaccharide and cordycepin in the solid fermentation of Cordyceps militaris were increased by 44.8%， 92% and 146%， respectively. There was no significant difference in body mass and organ coefficient among different groups. The intake of medium and high dose of SSF product could reduce the coefficient of testicular fat pad (P < 0.05)， and had a significant effect on the induction of cellular immune regulation in mice (P < 0.05). The SSF product decreased the diversity of intestinal flora. The abundance of conditional pathogenic bacteria decreased significantly， and the abundance of beneficial bacteria increased significantly. The results showed that the SSF product was safe and non-toxic. A certain dose of SSF product could reduce body fat， enhanced immune function， reduced the abundance of conditional pathogenic bacteria， promoted the proliferation of beneficial bacteria， and had the function of immune regulation and promoting the intestinal health of mice.