To establish a high performance liquid chromatography(HPLC) method for quantitative determination of Synephrine in Simotang. Method: DIKMA Diamonsil C18(5μ 250×4.6mn) for column,methanol-water-0.02mol/L phosphoric acid(69.9∶30∶0.1) for mobile phase,225nm detective length,1.0ml/min for flow rate,temperature 30℃. Results:For Synephrine,the linear rang was from 0.48 to 2.40μg (r=0.9991). Conclusion: This HPLC method for quantitative determination of Synephrine in Simotang oral liquid is simple and has high accuracy and good stability.It c...