Abstract: The extraction technology of coix seed oil was studied by microwave-assisted extraction.Based on single factor experiment,the Box-Behnken experimental design combined with response surface optimization was applied to optimize the extraction process of coix seed oil.The single factor experiment results showed that the ratio of ethanol to material was 12:1 mL/g,microwave extraction temperature was 60 ℃,microwave extraction duration was 15 min,microwave extraction power was 600 W,respectively. The results of response surface test showed that the optimal process parameters were ratio of ethanol to material 12.39:1 mL/g,microwave extraction temperature 60 ℃,microwave extraction duration 920 s,microwave extraction power 621 W. Under these condition,the yield of coix seed oil reached to 9.31%±0.10%,which was close to the predicted value of 9.41%,indicating that the microwave-assisted extraction process of coix seed oil optimized by response surface method was feasible.