A method based on ant colony optimization (ACO) was put forward for solving the problem of multiprocessor task scheduling in Vehicle Management System(VMS).Taking task number task grade task load and the relation between task and flight status into consideration the single processor risk coefficient function was designed.To balance the risk coefficients among the processors the objective function of task scheduling was established.Then the process of ACO for solving VMS task scheduling problem was given.A suboptimal scheduling scheme was obtained through simulation which verified the effectiveness of proposed method.