OBJECTIVE：To establish a method to determinate the content of paeoniflorin in Bailing tablet，and to evaluate the uncertainty of results. METHODS：HPLC was performed on the column of Platisil C18 with mobile phase of water - acetonitrile（87 ∶ 13，V/V）at a flow rate of 1 ml/min，the detection wavelength was 230 nm，the column temperature was 25 ℃ and the injection volume was 10 μ l. Quantitative analysis was conducted for the processes and procedures and the uncertainty was evaluated. RESULTS：The linear range of paeoniflorin was 0.100 1-2.502 8 μg；RSDs of precision，stability and reproducibility tests were lower than 2.0％，recovery rate was 98.7％-100.9％（RSD＝0.86％，n＝6）. Reference substance amount，elution produce and the accuracy of method had great effect on the uncertainty. CONCLUSIONS：The established method can be used for the content determination of paeoniflorin in Bailing tablet，and the uncertainty evaluation provides reliability for the method.