A new method for quantitative determination of icariin in Epimedii Herba by high performance liquid chromatography was established. A reversed-phase system with $a;{mu}Bondapak;C_{18}$ column using methanol in water(15% to 70%, gradient elution) as a mobile phase was developed. Icariin and spinosin as an internal reference were detected at 350 nm and the analysis was successfully carried out within 30 min.