Abstract: The garlic was pretreated by ultra-high pressure treatment to improve the antioxidant activities of aged garlic extract. The effects of different conditions (treatment pressure, holding time, ethanol concentration and solid/liquid ratio) on antioxidant activities of aged garlic extract (AGE) were investigated by determining the DPPH free radical, HO free radical and total antioxidant capacity. Combined with the results of the changes of S-allylcysteine, S-allylcysteine sulfoxid and total sugar content during the soaking treatment, the optimal process conditions were finally obtained. The optimal conditions were as follows:treatment pressure of 200 MPa, holding time of 5 min, ethanol concentration of 10%, solid/liquid ratio of 1:9 g·mL^-1 and soaking time of 55 d. The results showed that the AGE produced by ultra-high pressure pretreatment has a high antioxidant activity with the S-allylcysteine content of 1.9 g/kg (dry weight), in line with the standard of commercial AGE products. This study not only significantly shortened the production time, but also provided the technological support for the research and development of aged garlic products.