Abstract: To optimize ultrasound-assisted extraction technology process condition of antioxidants from Lobaria Pulmonaria by central composite design-response surface methodology. For the evaluation of the ability of extract to scavenge free radicals,a DPPH free radical system was constructed. Based on ethanol concentration,liquid to solid ratio,extraction time of single factor experiment,the principle of design for 3 star factor 5 five level response surface methodology was applied. The ethanol concentration of 85.0%,liquid solid ratio of18.6m L/g,extraction time of 20.0min were selected as the optimum conditions. The extraction under these conditions presented a DPPH radical scavenging ratio was 91. 69 %, with the theoretical 92. 829 % for the relative error of-1.227%. Central Composite Design-response surface methodology was highly predictive in experimental design.