Abstract: Plenty of flavonoid components existed in the leaves of Laurus nobilis L. This study determined the optimized conditions of microwave-assisted extraction of flavonoids from the leaves of L. nobilis,a natural spice,through single factor experiment and orthogonal experiment as follows:microwave extraction temperature was 80 ℃, the ratio of solvent to material was 40 ∶ 1( m L ∶ g), the ethanol concentration was 50 %, and the microwave extraction time was 10 min. Under the proposed conditions,the final yield of flavonoids was 7.64%.The DPPH radical scavenging activities of the extract were determined and the antioxidant activities to human colon cancer cells(HT29) of flavonoids from the leaves of L. nobilis were evaluated by cell model. The results clearly demonstrated that the flavonoids from L. nobilis got a CAA unit of 77.86,and possessed significant antioxidant activities.