Abstract: Based on single factor experiments,the yield of volatile oil as an evaluation index,the best technology of microwave-assisted extraction of volatile oil from Shaanxi-fringed pink was determined with response surface method,and the antioxidant activity of the extracted volatile oil was studied. Results showed that,the optimal conditions of microwave-assisted extraction were:Microwave power was 500 W,liquid-solid ratio was 20:1 mL/g,extraction temperature was 46 ℃. Under these conditions,the yield of volatile oil was 3.19%±0.46%,which was in line with the model predicted value 3.27%. The model was reasonable and reliable. The antioxidant tests in vitro showed that the volatile oil extracted by microwave method and the volatile oil extracted by ultrasonic method(power 120 W)under the same conditions had a good dose-effect relationship for DPPH· and O₂^-· scavenging capacity. Within the experimental concentration range,the IC₅₀ values of DPPH· free radical scavenging of volatile oil extracted by microwave and ultrasonic methods were 0.82 and 0.73 mg/mL respectively,and the IC₅₀ values of superoxide anion free radical scavenging were 0.68 and 0.81 mg/mL respectively.The results indicated that the volatile oil from Shaanxi-fringed pink had certain antioxidant activity,and the scavenging abilities of the volatile oil obtained by different extraction methods were slightly different for different free radicals.