Abstract: This study was to decolorize sasanquasaponin ( SQS) solution effectively by reduction method. The response surface methodology ( RSM) was used to optimize conditions for blanching SQS solution. The following parameters: dosage of blanching agents ( KBH 4 and NaHSO 3) , pH of the solution and reaction temperature were the variables.The optimal conditions determined by response surface methodology were: the dosage of KBH 4 was 1.2% ( w /w) , the dosage of NaHSO 3 was 2.2% ( w /w) , pH of 4.8 and reaction temperature of 51.0℃.TheΔE value under the optimal condition was 31.324 ± 0.378 and the yield of sasanquasaponin was 95.8%.Further detection of LC-MS/MS showed that bleaching agents did not degrade the structure of sasanquasaponin.