The polarographic behavior of icariin in various electrolytes was studied. It was found that a well defined peak was obtained in 0.05 mol/L ammonium sulfate supporting electrolyte at a potential of -1.51 V (vs Ag/AgCl). An excellent linear relationship was obtained between the concentration (1.28-3.85 X 10(-6) mol/L) and peak current. The method can be used to analyze flavonoids in small amount of medicinal herb samples.