The target assignment method was wholly studied from the perspective of engineering application, which includes some problems ought to be solved, the calculation method of assignable zone, the overall approach and flow, and the optimal arithmetic. Moreover, aiming at the problem that the antiaircraft missiles have different killing zones for different target types, a new approach of target assignment was presented which could improve the design effects of the weapon systems by limiting the calculation occasion of target to participate in assignment scheme. The handling method which adopts traditional Hungary Arithmetic for target assignment was introduced, and a new method based on the heuristic approach was presented, which can improve the functioning efficiency. Simulation results showed its feasibility.