Abstract: For further improvement of optical and laser induced damage properties of the thin films equipped on three harmonic of YAG laser system, different test methods were used to analysis the correlations between optical constant, crystalline structures, surface roughness, weak absorption and laser induced damage threshold of several thin films fabricated by reactive electron beam deposition process with different ultraviolet materials. The weak absorption and the bandgap limited the laser-induced damage threshold, rather than the surface roughness increased by the appearance of crystalline structures. Two laser damage processes were observed as that in higher weak absorption material, small damage expanded step by step when it absorbed the pulse laser energy, while in lower weak absorption material, a sudden damage occurred when the absorbed laser energy were higher enough.