The phenomenon had been noticed that penicillium in banana juices could secrete some antioxidants which had non-enzymatic oxidative discoloration activity. Strain No. 18 showed highest antioxidant activity and could be used as tested strain. Antioxidant activities of penicillium culture solution were studied. Antioxidants in penicillium culture solution were isolated,purified and detected for the total antioxidant capacity,DPPH·free radical scavenging capacity,hydroxyl radical scavenging capacity and superoxide anion removal capacity. Penicillium culture solution was extracted with ligarine and ethyl acetate respectively. The ingredients in aqueousphase were separated by the HP20 macroporous resin column chromatography and polydextran gel column chromatography G-75. The results showed that the effective compound could scavenge DPPH·,OH·,O2-·in a concentration-dependent manner.