OBJECTIVE:To establish a HPLC method for the content determination of baicalin in Pneumonia I mixture.METHODS:The assaying was conducted on a ODS C 18 column with methol-0.06%H 3 PO 4 (43∶57)as mobile phase,the detection wavelength was278nm,the column temperature was25℃and the flow rate was1.0ml/min.RESULTS:The linear concentration range of baicalin was0.1875?g～1.5?g(r=0.9998)with average recovery rate at99.63%(RSD=1.00%,n=6).CONCLUSION:This method is simple,accurate and reproducible,and it can be used for the quality control of baicalin.