Projectile dispersion has a great impact on firing methods and fire application. In order to compare and analyze the characteristics of the dispersion of uncontrolled rotating projectile with elevation, the 6D trajectory of a large caliber grenade at different position elevations is simulated based on the rigid external ballistic model of rotating stable projectile (6D model) and the average meteorological conditions at high altitude. Monte Carlo method is used to simulate and analyze the variation law of projectile dispersion with position elevation, and the influence of position elevation on projectile dispersion is studied. The results show that the projectile dispersion decreases with the increase of elevation at the same firing angle. When the position elevation is large, the projectile dispersion performance is better than that at low altitude.