Abstract: The effects of main factors ( pressure, temperature, extraction time, particle size) of soybean oil by supercritical CO2 extraction were studied, and the experimental conditions were optimized with soybean as raw material.Through single factor experiment and the orthogonal experiment, optimum conditions of supercritical CO2 extraction technology were temperature 45℃, pressure 25MPa, granularity 50mesh, extraction time 60min. The extraction of soybean oil rate reached 21.48%.The influencing order of soybean oil extraction rate were as follows:grain > pressure > extraction time > temperature.