A plasma sound wave detection method of laser shock processing (LSP) technology is proposed. Speciments of Ni-base superalloy are used in this paper. A convergent lens is used to deliver 1.2 J, 10 ns laser pulses by a Q-switch Nd:YAG laser, operating at 1 Hz. The influence of the laser density to the shock wave is investigated in detail for two different wavelength lasers. Constant amplitude fatigue data are generated in room environment using notch specimens tested at an amplitude of vibration 2.8 mm and first-order flextensional mode. The results show that LSP is an effective surface treatment technique for improving the high cycle fatigue performance of Ni-base superalloys having a factor of 1.62 improvement in fatigue life.