Abstract: The technology for extraction avenanthramides from oat bran was optimized by Orthogonal design, and purified by macroporous resin; Meanwhile, the vitro antioxidant activity were studied. Results show that the optimal parameters for extraction are ethanol / water / acetic acid 80/19.9/0.1, temperature 60℃, solid-liquid ratio of 1︰8, the extraction time is 2 h. Under such conditions, the yield of avenanthramides is 5.29%, the content of avenanthramides can be increased up to 19.2% after being purified by AB-8 macroporous resin. It also show that the purified avenanthramides extract has strong capacity of scavenging OH·, O2-· and DPPH free radical, the scavenging capacity are 79.4%, 82.2% and 78.0% as large as that of α-tocopherol respectively.