Abstract: The microstructure of sunflower seeds was observed by confocal laser scanning microscope( CLSM).The effect of particle size of material on oil extraction yield was investigated.The result showed that the particle size of the sunflower seed smaller than 30 μm could obtain the highest oil yields,the total oil yields was 87.12% by aqueous extraction processing( AEP).However,AEP could produce more oil rich emulsion.In order to increase the total oil yield,this study was also compared various demulsification treatments,including: ethanol assisted,thermal,high speed shear,freeze- thaw and enzymatic treatments. The results showed that freeze- thaw and ethanol assisted treatments methods obtained better oil recovery yields( 94.01% and 92.02%,respectively).In addition,the total oil yield was increased to 95.63%.What's more,the quality of oil obtained by aqueous extraction processing was very high and was comparable with the quality of cold- pressed oils. The optimization of sunflower seed oil extraction process technology was reasonable and feasible.