We consider an operations problem for an unmanned combat vehicle (UCV) in a military. The problem is to schedule a patrol path for the UCV on a set of key terrains with the objective of minimizing total threats being generated by a possible infiltration of the enemy in a forward area. In this study, threats on each key terrain are increased in nonlinear way by interval of patrols and the key terrains can be patrolled multiple times with a given mission time (2-hour) for the UCV. In order to get the objective, we make a sequence of patrolling key terrains to minimize the total threats. For making the sequence, we develop four heuristic algorithms which are composed of two-step procedure. For evaluation of the performance of the proposed heuristic, computational experiments are performed on randomly generated data sets, and results show that the algorithm gives a good solution for the problem in a short time.