Abstract: The extraction and purification process of phytosterol were studied from corn silk by saponification. The highest extraction yield of 10.5886 mg / g total phytosterol was acquired by the ultrasonic assisted method. The optimal extraction conditions were determined by single factor and orthogonal test as follows: 220 W ultrasonic power,55 min extraction time,ultrasonic temperature 35 ℃,and 12∶ 1 ratio of liquld- material( m L / g).Phytosterol crystal was achieved with ethyl acetate as solvent after being extracted by chloroform.The purity of the crude phytosterols was 92.76% with 47.5% ± 0.24% β- sitosterol and 36.7% ± 0.13% campesterol,respectively after recrystallation by methanol.