Based on ultrasonic method the experimental results were evaluated by the yield of soybean powder lecithin.The lecithin was extracted using ethanol.The optimum extraction parameters were obtained by orthogonal design method.The results indicated that when the concentration of ethanol,temperature,extraction time,ratio of solid to liquid and extraction times were 80%,40 ℃,50 min,1 ∶3.0 and 2,respectively,the lecithin from soybean powder was obtained of 12.85%.