A new Differential Evolution algorithm with dual population was proposed for the static Weapon-Target problem. There are two different types of population in the new algorithm with one is floating-point coded and the other is sequence number coded. During the evolution a new mapping operation was proposed to generate the corresponding sequence population from the floating-point population. And the sequence population was used to guide the direction of the new algorithm by deciding which one between the floating-point individual and its rival will exist in the next generation. Initial simulation results the new algorithm is effective and efficient in solving the static Weapon-Target problem which is NP-complete.