The damage rule of aircraft structure material LY-12 CZ with projectile is tested and investigated by accelerating the 7.62 mm pill with the ordinary gun. Through the analysis of the experimental results, the conclusion shows that there is a linear relationship between the damage size and the cosecant value of pill velocity angle; the damage size is distributed in normal school. Simultaneously the damage mode and the mechanism are analyzed, and then a battle-damage degree forecast experimental model of LY-12 CZ is put forward in the light of LATDAM.