Abstract: This article uses the ultrasonic extraction of Cordycepin in cultured Cordyceps militaris,and adopting the high performance liquid chromatography (HPLC) method for the determination of cordycepin.When chromatographic column was ZORBAXExtendC18,water and methanol (95:5) as mobile phase,flow rate of 1.00 mL/min,detection wavelength of 260 nm,sample quantity 10 μL as a condition of chromatography,cordycepin in 10~1000 μg/mL has good linear relationship (S=3.3×104C－41890，R2=0.9999),the recovery rate:103.37 %,and RSD:2.26 %.

Key words: Cordyceps militaris fruiting body, Cordycepin, High performance liquid chromatography