In order to research the hole-making characteristics of high volume fraction silicon carbide particle reinforced aluminum matrix (SiCp/Al) composite material thick plates processed by laser, the hole making test of 4mm thick plate was carried out using different laser processing parameters. And the formation mechanism of the recast layer and its surface cracks in the hole made by the ultraviolet picosecond laser was analyzed. The influence of key laser processing parameters (laser power percentage and scanning speed) on the hole recast layer was obtained. The results of the experiment show that there is a recast layer of hundred microns in the picosecond laser processing of SiCp/Al composite thick plates. The thickness of the recast layer does not change monotonously with the increase of laser power, and the thickness is the smallest at 100% laser power with value of 99.5μm; the thickness increases with the increase of the laser scanning speed, and the smallest value is 71.2μm at a scanning speed of 100mm/s with. In addition, the recast layer of the thick plate ultraviolet picosecond laser processed SiCp/Al composite has a “crescent” arc-shaped morphology. At the same time, there are significant horizontal and vertical cracks on the surface of the recast layer. This research provides theoretical guidance for low-damage micro-hole machining of SiCp/Al composites with picosecond laser.