In order to get the key parameters of the Projectile Point of the sub-warheads, the external trajectory equation of bullets is constructed and the rule of the cluster warhead's fall point is analyzed based on a model of warhead with sub-warheads and the structure of excessive segments arrangement. This paper proceeds from the operational effectiveness, elects a search algorithm based on the shape and area of target. After simulation investigation, the use of this algorithm can ensure that the warheads effectively cover the whole area of the target, and the maximum error is only 2.5%. Therefore, the algorithm is efficient in improving the operational effectiveness of the shrapnel, and also can provide a new thought for the use and the development of the shrapnel.