Abstract: There are differences among parameters for soybean oil and soy protein extraction using enzyme assistant techniques. The object of this research was to optimize enzyme assistant technique using fuzzy evaluation method based on soybean oil and protein, and extraction parameters of high soybean oil and protein was obtained. The parameters were following, enzyme dosage 1.85%, temperature of enzyme hydrolysis 50℃, time period 3.6 h, ratio of material to liquid 1﹕6, pH value 9. Relatively bigger recoveries of soybean oil and protein were 92.76% and 93.81% respectively. The results of Scanning Electron Microscope, energy disperse spectroscopy and optical microscope showed that soybean oil releasing depended on situation of protein hydrolysis for soybean after being extruded and expanded. Structure of soybean cells was completed destroyed after extrusion and expansion, while lipoprotein was not destroyed, so the soybean protein needed to be hydrolyzed completely to release soy oil. The result shows that it is a feasible way to prove soy oil and protein yield using enzyme assistant method after extrusion and expansion.