Aiming at the problem that the centralized command and control model in high dynamic air combat environment is easy to be interfered and redistribution efficiency under emergency situations is low, a fully distributed cooperative air combat decision-making model based on improved combinational auction is proposed. The fighter agents construct combination biddings using greedy algorithm. The task is allocated and coordinated through information exchange and mutual negotiation to achieve the same attack plan. Simulation results show that the algorithm is efficient and its time efficiency for practical needs of warfield.