To solve the problem of the great influence of damage area of fragment of existing calculation methods by grid density, establish a method of damage area of fragment by triangulation. And analyses the proximity height of air ammunition to personnel target. The personnel of kinetic energy threshold of fragment is 98J and the density threshold is 1.33 trunk of per square meter. The result reflects that the damage area of personnel increases by the increase of fall angle that the influence of fall velocity increase by fall angle, the influence of fall velocity to damage area of personnel is concerned with fall angle and