A new method is given for task allocation of multiple Unmanned Aerial Vehicles (UAVs). Firstly, the capability function of the UAV is established, and the methods for calculating the multi-UAV cooperative attacking position and the pitch angle of the UAV are given by using the Jacobian matrix of capability function.The UAV's damage cost index function, voyage cost index function and income value index function are established. The dynamic task allocation method for multi-UAV cooperative combat is presented. A simulation experiment has been conducted, and the result shows that: compared with the task allocation methods not considering the capability function, our method obtains greater target income value and can improve the multi-UAV cooperative attacking capability.