The contents of baicalin and baicalein in Shuanghuanglian Powdery Injection have been determined by the method of HPLC-ECD under following conditions: column-ERC-ODS-1161, 6 mm x 100 mm; temperature-55 degrees C; mobile phase-0.1 mol/L KH2PO4, acetic acid and tetrahydrofuran (1000:100:190); flow rate-0.8 ml/min; detector voltage-+650 mV. The result shows the limit of detection for baicalin and baicalein to be 25 ng and 50 ng respectively, with an average recovery of 100.1% and 99.7% respectively. Highly reproducible, rapid, simple, convenient and accurate, this method is good for the content determination of baicalin and baicalein in Chinese medicinal herbs and preparations.