Abstract: In order to engineering the 800 nm lasers used as the light source of laser illumination in wide-temperature range, an end-face pumped solid laser was used in the experiments. The output 1064 nm laser beam of the diode array end-face pumped Nd : YAG laserpassed through a KTiOPO₄ (KTP) crystal, then 532 nm laser was obtained from frequency doubling of 1064 nm. Finally, the output 800 nm laser was realized after the process of optical parametric oscillator using 532 nm laser works as pump source. Active temperature controlling and multi-wavelength matching was used for laser diode array. Active heating was used for KTP. The experiment results show that the 800 nm lasers is realized with energy over 20 mJ, pulse width 12 ns and divergence angle 3.5 mrad; It can work over 3 min in 25 Hz in wide-temperature range -40 ℃~55 ℃; The output laser of this design has higher peak power, better laser beam quality and narrower pulse width compared with directly using 808 nm semiconductor laser as the light source, and these advantages are conducive to increase the working distance of laser illumination and accuracy. The temperature adaptability of this laser is high when it is worked as the light source of the active laser illumination imaging. So it can meet the demand of engineering, especially the demand of the wide using temperature.