A method and apparatus for nanocrystallizing a metal surface by laser-induced shock wave-accelerated nanoparticles. The apparatus comprises a control system, a light guiding system, a workbench control system and an auxiliary system, wherein the auxiliary system comprises an air compressor, a paint feeder device, a nanoparticle nozzle, a powder feeder device, an exhaust, a sealed working chamber and a metal nanoparticle recycler device. The method comprises the following steps: pre-processing and fixing a workpiece; activating the air compressor to feed a powder; controlling and adjusting the paint feeder device to eject a black paint; transmitting a high-power pulse laser beam; recycling excess metal nanoparticles; and rinsing non-vaporized/ionized black paint off a surface of the workpiece.