Abstract: Transparent ceramic is a new kind of transparent material with excellent optical performance and mechanical properties for the potential application of transparent armor arranged with low areal density, high transmittance and better protection capability. In order to explore the bullet proof mechanism of YAG transparent ceramic composite target, an experiment of ceramic composite target subjected by 12.7 mm armor-piercing incendiary was conducted. Based on the ballistic testing technique and high-speed camera technology, the damage characteristics of each layer of transparent ceramic composite target and the damage form of projectile body were determined. The change of the back convex of the backplane was measured by the data in high-speed photography. On this basis, a finite element simulation method of YAG transparent ceramic composite target resistance process was established based on the AUTODYN finite element simulation software platform. The bullet proof mechanism of transparent ceramic composite target with typical structure was studied based on finite element simulation. The effect of thickness change of transparent ceramics and polycarbonate on its ballistic performance was analyzed. The results show that the transparent ceramic armor can effectively consume the impact energy of the projectile body by the high strength crushing of the transparent ceramic panel. The layer of glass consumes the impact energy of the ceramic cone, and the backplane absorbs the residual kinetic energy, so as to realize the transparent armor protection with low areal density. The increase of transparent ceramic panel destroys the projectile body more effectively so as to improve the ability of armor protection. Polycarbonate can effectively protect low areal density of composite target in a certain thickness range.