Cooperative control strategy can support coordinated attack for multi-UAV in threat environment,and achieve the greatest combat effectiveness with time constraint.It is a crucial problem with significant theoretical value and great practical value.Firstly,a cooperative path planning based expanded Voronoi diagram was proposed.The threat environments considered different types of threats and no-fly zones with different threat distances.Line-of-sight of path shortening algorithm and smoothing algorithm were proposed to realize dynamic optimization of the paths.Secondly,time error signal was obtained from real time-to-go and the estimated time-to-go by adopting a simple online time-to-go estimation method.Dynamic path planning on the basis of the estimated path was done to satisfy the impact time constraint.At last,simulation results proved validity and real-time.This method can support cooperative attack for multi-UAV.