In multiple Unmanned Aerial Vehicles (UAVs) cooperation for target area coverage searching, the traditional searching strategy can not make effective detection to moving targets. To solve the problem, a multi-UAV oblique line cooperative searching strategy is proposed, aimed at reducing dead zone and improving the effective coverage area of UAV formation. The UAV sensor model is given, analysis is made to the principle of moving target searching, and the scanning probability model is built up. Simulation results show that the improved searching strategy can accomplish the searching task more effectively. Comparison proves the advantages of the proposed method.