Combat task assignment is one of key issues of conventional missile operations research. Considering combat situation of conventional missile and constraints such as operational intention and task coordination, the model of task allocation was established by use of parallel ant colony algorithm. Based on muti-ant-colony algorithm and considering the characteristics of conventional missile combat task assignments, the sub-colony coordination and communication strategies based on task competency assessment and state transition rules based on the cost of task were designed. Ant colony algorithm of task assignment problem solved in parallel was presented. The correctness of the model was shown by simulating. According to simulation results, it can be found that this method can effectively solve the problem of combat task assignment of conventional missile.