Abstract: The LD side-pumping structure was designed to meet the requirement of miniaturization and spot uniformity of the laser system for weapon systems. The compact laser resonator was designed. In this design, the thermal effect is compensated by the total reflection concave mirror. The laser output, whose average single pulse energy is 96mJ (energy fluctuation ＜6%), pulse width is 10ns and divergence angle is 3mrad was obtained as the current is 60A and the frequency is 20Hz. The laser system can still work stably when the temperature rise to 50℃.