Hypervelocity impact (HVI) characteristics of Ti6Al4V/Ly12 Al/polyamide fibre density-grade thin-plate are investigated experimentally in a velocity range of 4.0–6.5 km/s by using two-stage light gas gun. The perforation in target, damage to witness wall, and ballistic limit curve are obtained and compared with those in the case of aluminum thin-plate. The results show that the diameter of the perforation hole is larger than that of aluminum thin-plate, the crater size in witness plate is smaller, and the ballistic limit curve is 50% larger than the latter. The analysis of shock wave propagation and the calculation of energy dissipation property in the density-grade thin-plate show that higher peak shock pressure is produced in it, and it has longer pressure duration time. Thus, more dissipation energy is consumed than in the case of aluminum thin-plate. So the density-grade thin-plate has a very good performance in withstanding HVI, and is promising in engineering application, e.g. protecting spacecraft from HVI of micro-meteoroid and orbital debris.