The n-hexane was used as extraction solvent, and the ultrasonic-assisted extraction parameters of Panicum miliaceum L. shell oil were optimized by response surface methodology based on the single factor experiment of ultrasonic power, liquid-solid ratio, extraction time and extraction temperature. The results showed that the optimum extraction parameters were as follows: the ultrasonic power was 400 W, the liquid-solid ratio was 12∶1 (mL/g), the extraction temperature was 70 ℃, and the extraction time was 50 min, and the yield of Panicum miliaceum L. shell oil reached 6.95% under the optimal condition. Five kinds of fatty acids were identified by GC, the main fatty acids of Panicum miliaceum L. shell oil were linoleic acid (70.10%), oleic acid (20.00%), palmitic acid (8.79%), linolenic acid (0.89%) and eicosenoic acid (0.21%), respectively.