Abstract: Taking walnut leaf as test material, the effects of extraction time, extraction temperature, liquid-solid ratio and ethanol concentration on the extraction rate of flavonoids in walnut leaf were studied by using ethanol reflux extraction method, and the extraction conditions were optimized, in order to provide reference for the development and utilization of flavonoids in walnut leaf.The results showed that the optimum conditions for extracting flavonoids from walnut leaves by ethanol reflux extraction were extraction time 3 hours, extraction temperature 60 ℃,liquid-solid ratio 50∶1 mL·g^-1,ethanol concentration 80%,and the maximum amount of flavonoids extracted was 20.50 mg · g^-1.The flavonoids extract had a stronger antioxidant capacity, although its scavenging rate of DPPH free radicals and total antioxidant capacity were not as good as those of vitamin C.