Abstract: A damage assessment system was developed, which can be applied to damage assessment of penetration projectiles attacking concrete buildings. That includes a data format to describe the internal logic of concrete buildings, and a.XML file format for associating the data format with the building model; a projectile modeling system and a power analysis system based on material database and research results on detonation physics, etc; a vulnerability analysis system based on AHP and Function Damage Tree; algorithms for simulating explosion process and penetration process. At last, we analyzed the effect of aiming position, penetration depth and CEP radius on the damage result, which could be a reference for related research.