Quantitative method of flavonoids from leaves of Chenopodium glaucum(FLCG) was optimized using UV-vis spectrophotometry. In order to research the optimized extract technology of FLCG, the single factor trials and response surface methodology were involved. Except these, the anti-oxidant function of FLCG was evaluated by O2-?and ?OH radical. The results showed that it was feasible to measure the contents of FLCG with 3% AlCl3 at 273.5nm. RSD was 1.42%,1.83%,0.86%and 0.60%, respectively. The optimal condition was as follows : the ethanol concentration was 57%, solid-liquid ratio was 1:20 and microwave power was 500W for 7.8 minutes. Under this procotol, the yield of FLCG was 3.292%. FLCG had excellent scavenging effect on ?OH and O2-? radical in this research, the scavenging effect of FLCG on antioxidant activity had a positive correlation with its concentration.