The purpose of the invention is to provide a laser shock prediction method based on laser fluctuation and surface laser light scattering and a device. The surface roughness of a part after impact is predicted through laser energy spatial distribution data measured in real time to set laser device input parameters; and the data of the surface roughness variation of the part is measured in real timethrough a laser scattering measurement method to correct the laser device input parameters in real time, so that the part finally meets the design requirements. The invention also discloses a laser shock reinforcing device based on the laser beam parameter fluctuation and part surface laser scattering measurement data, which comprises a computer, a laser shot blasting device, a part robot, a partrobot controller, a measuring laser device, a detector, and an information collecting system. The laser shock reinforcing device based on the laser beam parameter fluctuation and the part surface laser scattering measurement data can perform laser shot blasting through the real-time variation of the laser energy data and the change of the surface roughness data of the part to improve the surfaceprecision.