When the UAV cluster is attempting formation flight, electromagnetic silence should be maintained as much as possible to avoid external interference, and few electromagnetic wave signals should be emitted outward. In order to maintain the formation, a purely azimuthal passive positioning method is proposed to adjust the position of UAVs. In order to reduce the deviation of the UAVs from the ideal position, we first establish an optimization model by finding the closest position to the ideal coordinates of each receiving UAV under the constraint rule as the objective function, and use the signal UAV traversable coordinates as the constraint, establish an iterative optimization distance model, and use the traversal algorithm and iterative algorithm to find out the ideal position of the UAV under the constraint, and finally be able to reduce the total actual deviation of the UAV to about 0.159 m.