The study established a UPLC-MS/MS method that is used for simultaneous determination nine major bioactive compounds of Dachengqi Tang in rat plasma. Using Aglient C18 column (2.1 mm x 50 mm,1.7 microm) was chromatographed, using methanol-5 mmol x L(-1) ammonium formate mobile phase gradient, elution 0.3 mL x min(-1). In the plasma pre-treatment process, not only the method of methanol and acetonitrile protein precipitation was investigated, and different factors extraction solvent, the type of the scroll time, the number and the type of extraction solvent, the extraction volume of the extraction solution of liquid-liquid extraction is investigated. Finally, with ibuprofen as an internal standard, using ethyl acetate liquid-liquid extraction method pretreatment blood, N2 dry reconstituted supernatant after centrifugation UPLC-MS/MS analysis, in electrospray ionization (ESI) negative mode, using multiple reaction monitoring mode for testing. The linear range of emodin, rhein, aloe-emodin, chrysophanol, magnolol, honokiol, hesperidin and hesperitin is 0.33-660, 0.40-792, 0.41-827, 0.34-680, 0.45-907, 0.46-927, 0.43-867, 0.34-683, 0.39-787 microg x L(-1) respectively, good linear relationship; and extraction recovery were greater than 69.39%, days after the day of the RSD is less than 15%. This method can be used to study the rat gastric large bearing gas after Dachengqi Tang, the simultaneous determination of nine components in plasma for its pharmacokinetics and efficacy material base to provide a theoretical basis.