High-energy short-pulse lasers have been increasingly used in the field of material processing. Comprehensive understanding of the laser shock peening effects is crucial to future improve the surface mechanical of pure copper efficiency and stability. Herein, we investigated laser shock peening, which may enhance the mechanical properties of metals and alloys. The microstructural evolution and surface mechanical properties of pure copper after laser shock peening were evaluated. Typical high-density dislocations and twin grating after laser shock peening were analyzed. The mechanism of laser shock peening-induced grain refinement was subsequently analyzed. The laser shock peening method effectively enhanced the surface mechanical properties of pure copper. The microhardness of pure copper increased obviously after laser shock peening. However, laser overlap percentage plays a key role in improving surface mechanical properties. In the present work, a 50% overlap was optimal, with the surface hardness after laser shock peening improving by 47%.