Residual microstructure associated with the crater in 15% Ti–6Al–4V wire mesh reinforced 5A06 alloy (TC4 m /5A06) composite thin target impacted by Al projectile with the speed of 2.5km/s were investigated. The depth and diameter of crater impacted by Al projectile with the diameter of 1.6mm are 1.62mm and 2.8mm, respectively. At the back face, bulge with height of 0.5mm is produced along the impact direction and cross-shaped cracks and spalling form at the top of the bulge. With projectile diameter increasing to 2mm, composite gets perforated and the diameter of perforation becomes 3.2mm. Microstructured observation of crater impacted by Al projectile with the diameter of 1.6mm shows that in the region near the pithead and around the center of crater, decohesion occurs at the interface between TC4 wire and Al matrix and the direction of decohesion is in agreement with the outline of crater. In the region at the bottom of the crater, there appears an adiabatic shear band (ASB) in a TC4 wire and two sections of wire slide with each other along the direction of ASB with a distance of 200μm. TEM observation reveals that block-shaped Ti 2 Al phase with size up to 1μm forms in the ASB at the bottom of the crater after high speed impact. Besides, amorphous structure, nanograins and ultrafine grains are found in Al matrix at the bottom of the crater.