Using powered soybean phospholipid with low PC content as raw material, the process of desugarization was optimized by the orthogonal experiment based on the single factor experiment. The results showed that the desugaring rate arrived 89.7% and the content of sugars in the extractive raw sugar was 89.2% when the optimum parameters were chosen as follows : temperature 30 ℃, extractive time 70 min, volume ratio of hexane to ethanol 1∶〖KG-*2〗2, volume fraction of ethanol 50% and extraction for twice. The kinds of the removed carbohydrates and its content were determined by high performance liquid chromatography, which were stachyose, sucrose and raffinose，with contents of 71.1%，17.3%,6.6%，respectively.