In order to simulate and study the hypervelocity impact of space debris on dual-wall structure of spacecrafts, firstly a non-powder two-stage light gas gun was used to launch AL-sphere projectiles. Damage modes in rear wall of dual-wall structure were obtained, and while the law of damage in rear wall depends on projectile diameter and impact velocity were proposed. Finally, numerical simulation method was used to study the law of damage in rear wall. By experiment and numerical simulation of hypervelocity impact on the dual-wall structure by Al-spheres, and it is found that AUTODYN-2D SPH is an effective method of predicting damage in rear wall from hypervelocity impact. By numerical simulation of projectile diameter, projectile velocity and the space between bumper and back wall effect on damage in rear wall by hypervelocity impact, and fitting curves with simulation results, the law of damage in rear wall and dominant factors effect damage in rear wall by hypervelocity impact were proposed.