In this study, we consider formation control of a group of plural unmanned aerial vehicles (UAVs). New algorithm and control rules that create a form and direction are proposed. UAVs make the cooperative formation to perform a task. It is most important that the formation fly over the target point with keeping a precise form. To take the advantages of both formations that have no-leader and leader, each UAVs has same ability and there is no leader at the initial point. To make a directional formation, the limitation of velocity is applied. The shape of formation is decided by changing values in the limitation. In addition, applying the concept of plant hormone to the formation flight, one of the UAVs becomes “leader” when the value of hormone exceeds the threshold value. The formations of 4 UAVs are simulated using simple rules of a directional formation. The stability of formation is also discussed. The results show that the new rules of a directional formation bring accomplishment of the objectives.