Abstract: Shock wave merging happens when the waves have damped, for repetitively pulsed laser irradiation induced waves. The influence of laser duration on the wave evolution becomes important as the laser pulse interval is small. Thus the evolution of the shock waves was numerically studied with laser incident process being taken into account. Results show that the shock wave front is ellipsoidal at the beginning, and then becomes spherical gradually. The distance from the sphere center to the breakdown point decreases gradually to a constant value. Based on the application of laser shock wave merging, shock waveradius, shock wave length, and overpressure as functions of time and shock wave front radius were derived at the Mach number from 1 to 2．