Response surface methodology was used to optimize operating parameters of ultrasound assisted extraction of oil from Dunaliella salina.Ethyl acetate was the extracting solvent,and the yield of oil was the response value.The order of the effectors was: extracting time> extracting temperature> ratio of liquid to solid.The optimal conditions were: ratio of liquid to solid 29 mL/g,extracting time 35 min,extracting temperature 69℃.Under the optimal conditions,the oil yield was 15.92% and was consistent with the predicted value by RSM.Palmitic acid,oleic acid,linoleic acid and linolenic acid were the main fatty acids in D.Salina oil extraction,and the content of each was(13.80±0.26)%,(5.20±0.15)%,(8.55±0.16)%,and(23.15±0.24)%,respectively.