Experiments were carried out to investigate effects of extruding parameters on soybean oil yield extracted with enzyme-assisted aqueous extraction. It was found that extrusion and expansion parameters affected significantly on total soy oil yield. Optimal extrusion and expansion parameters for highest total soy oil yield were obtained using response surface methodology. Effect of extrusion and expansion pretreatment on soy cells was studied using light microscope and transmissive microscope. State of free oil and protein during hydrolysis was observed using light microscope. Ultrasonic assistant ethanol de-emulsification was found the effective method to destabilize the emulsion.