Using aqueous solution of 60％ ethanol, the isoflavones contained in the Soybean (Chungsun, Korea), Tawon (Suwon, Korea), Jackbean (Hongsung, Korea), Soybean (Jilin, China), Black Soybean (Jilin, China), Kidneybean (Jilin, China) and Soybean (California, U.S.A.) were extracted. In this work, the pretreatment step was composed of agitation extraction, filtration, concentration, ultracentrifuge, and membrane filtration. The analysis by C18 column was performed, and the mobile phase applied was linearly changed with A/B of 85/15-65/35 vol％ for 50 min (A water/acetic acid, 99.9/0.1 vol％, B acetonitrile/acetic acid, 99.9/0.1 vol％). Among the soybeans tested, the total amounts of the four isoflavones (daidzin, genistin, daidzein, and genistein) extracted by the soybeans from Korea, China and U.S.A. were 1.37, 1.60, and 2.25 mg/g, respectively. It was also found that the total amount of aglycone of daidzein and genistein from soybean (American California) was 144 μg/g, which was the largest for the soybeans experimented.