The hydrolysis of saponins in sealed tube with trichloride acetic acid using butanone as internal standard and monitoring with UV scanning were firstly applied in the extraction of Tribulus Terestris Saponins via pre-fermentation. The results showed that the extraction rate of Steroidal saponins via microorganism fermentation was 2.28 times higher than that without pre-fermentation. The optimal concentration of Trichloride acetic acid, internal standard, temperature for sealed tube and reaction time for the hydrolysis of Tribulus Terestris saponins were 15%, butanone, 120 ℃ and 1 h, respectively. The most suitable extracting solvent was found to be n-hexane. Results showed that the extract rate of steroidal saponins was greatly improved after microorganism’s fermentation. And the saponins hydrolysis in sealed tube with trichloride acetic acid was shown to be a simple and reliable monitoring method with promising application prospect.