The antioxidant activity of flavone extract from tillering onion in vitro was studied by measuring its scavenging ability and reducing ability of DPPH free radical, superoxide anion free radical, hydroxyl free radical, ABTS⁺ free radical and nitrite free radical. The results showed that the flavone extract from tillering onion had significant scavenging activity on DPPH radical, hydroxyl radical, superoxide anion radical, ABTS⁺, nitroso radical, with the maximum scavenging rates of 89.35%, 76.12%, 85.43%, 76.26%, 72.11%, respectively, and had good reducing ability. This study can provide a basis for the development and utilization of tillering onion resources.