Abstract: Camellia seed cake was a potential raw material for feed production. However， the nutritional composition of Camellia seed cake was imbalanced， and it contains anti-nutritional factors， which hinder was application in feed. Microbial solid-state fermentation can optimize the nutritional composition of Camellia seed cake through metabolic processes and reduce the content of anti-nutritional factors. Bacillus strain which was safe for feed application was used as the starting strain to investigate the changes in the contents of polyphenols， flavonoids， crude protein， amino acids， as well as tea saponins and tannins， in Camellia seed cake after solid-state fermentation. The results showed that， after solid-state fermentation， the contents of polyphenols and flavonoids were slightly reduced， crude protein， tannins and tea saponin in Camellia seed cake were significantly reduced. After fermentation， the tyrosine content slightly decreased， while the contents of other amino acids increased. Among them， the tea saponin degradation rate was the highest in Camellia seed cake fermented with Bacillus licheniformis. Through the optimization of fermentation conditions for tea saponin degradation in Camellia seed cake， the optimal solid-state fermentation conditions were determined to be initial water ratio of 100%， temperature of 35 ℃， inoculum size of 8%， and fermentation time of 60 h.