Abstract: In order to study the relationship between the amplitude of the shock wave in air and the amplitude of the shock wave in the workpiece, and the relationship bettveen time-of-flight of the shock wave in air and the compressive residual stress in the workpiece respectively, the acoustic emission sensor and the polyvinylidene fluoride piezoelectricity gauge were used to detect laser induced plasma shock wave in air and the workpiece.In the experiment, the workpiece is 45# steel,the absorption layer is Al foil,and the confinement layer is fluid overlays. The results show that with laser intensities increases, time-of-flight of the shock wave in air decreases nonlinearly,and the amplitude of the shock wave in air and workpiece increases nonlinearly, and the compressive residual stress closes to saturation.Finally, the empirical formulas for the amplitude of the shock wave in air and the amplitude in the workpiece,and for time of flight of the shock wave in air and the compressive residual stress in the workpiece were established respectively, which could provide theoretical reference for quality assurance of laser shock processing.