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 transformation law of damage area of fragment with fall velocity, fall angle and proximity height. 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; the influence of fall velocity to damage area of personnel is concerned with fall angle and the influence of fall velocity increase by fall angle; the damage area of personnel decreases by the increase of proximity height, and the best proximity height decreases by the increase of fall angle.