The invention discloses the use of paeoniflorin-6'-O-benzenesulfonate of formula I in treatment of Sjögren's syndrome. Paeoniflorin-6'-O-benzenesulfonate of the invention, which has definitely curative effect, is characterized superiorly in that, it could be taken clinically for a long time with small dosage, mild adverse reaction and good patient compliance. The molecular formula of paeoniflorin-6'-O-benzenesulfonate is CHOS, and the chemical structure is shown in Formula I.