For most of the traditional strategies that aimed at reducing the risk of complex network, they didn't consider the specific characteristics of aviation system, thus lack of accuracy. A new strategy which considers the reality of aviation network was proposed. Based on importance evaluation matrix and risk analyzing model, the function relationship between the risk of network and many factors were calculated, then apply particle swarm optimization to the allocation of defense resources. After running some tests on Chinese aviation network, the allocation result conforms to present situation, and significantly reduced the total risk of network compared with traditional strategies.