By means of analyzing component and source of major contamination in high-power laser facility to investigate impact law on damage resistant ability of large aperture optics surface, clearness control requirement of optics surface in high-power laser facility is obtained. The sampled contamination particles in high-power laser facility are analyzed by scanning electron microcopy. The contamination particles on optics surface are fabricated by natural setting method, damage threshold and law of optics are investigated by Nd∶YAG (SAGA-S). The results show that collected particles are about 20% metallic, 40% organic and 40% mineral, respectively. Both laser cleaning effect and laser induced damage occurrs during the laser irradiation. When the laser energy density is above 10.9 J/cm2 , the particles are removed by the laser energy density. But when the laser energy is above 14.6 J/cm2, damage points occur on the optical surface due to the contamination particle, and the laser induced damage threshold descends with the size of the particle.