Abstract: High-power all-solid-state sub-nanosecond lasers have the advantages of small size, low cost, narrow line width and high peak power. They have important application value in many fields. In order to obtain high-power sub-nanosecond laser output, a sub-nanosecond seed laser was first obtained through a passive Q-switched laser, and then an LD side pump module was used to design a dual-module dual-pass amplification experiment. At a repetition rate of 1 kHz, a laser output with an average power of 10 W, a pulse width of 816 ps, a line width of 39 pm, and a beam quality M² of less than 1.8 was obtained. The overall magnification the amplifier was over 95 times.