Abstract:To explore the effects of different fermentation conditions， namely， the fermentation time， yeast inoculation quantity， fermentation temperature， on the total content of saponin Rg1，Re，Rb1 on red ginseng. And based on the single factor experiment and using the response surface analysis of Box -Behnken （BB） experimental design to optimize the fermentation conditions. The results showed that The fermentation temperature， fermentation time， yeast inoculation quantity has an effect on the total saponin content of red ginseng and the order of effect as follows： fermentation temperature > fermentation time > yeast inoculation quantity. The optimum process was as follow： fermentation time was 41.80 h， yeast inoculation quantity was 0.89 g/L， fermentation temperature was 32.20 ℃ ， Under the optimal process conditions， the total saponin contents was increased 30.46 %.