A high-energy quasi-continuous-wave (QCW) laser diode-pumped regenerative amplifier was demonstrated for using as a radiation source of laser-induced plasma. The seed source was an all-fiber amplifier, provided pulse width of 454 ps and single pulse energy of 7.7 nJ at a repetition rate of 24.17 MHz and a central wavelength of 1063.9 nm. The solid-state regenerative amplifier used a Nd:YAG crystal was side-pumped by QCW diode bars. With this system, high stability and high energy was generated at wavelength of 1064.1 nm, with pulse width of 392.1 ps and output average power was 4.04 W. The single pulse energy and peak power was 8.08 mJ and 20.6 MW, respectively. The M2 factor was about 1.48. The laser system will use as a picosecond radiation source for the following laser ablation and laser-induced plasma spectrum analysis. In the previous work, the process of laser-induced plasma was simulated by fluid dynamics. The temporal and spatial distribution of electron density and temperature was successfully simulated, corresponding the process of laser irradiation on target were recorded for set of materials (Si, Al, Cu). Finally, the mechanism and evolution process of the picosecond laser irradiation target were obtained.