To study how laser pulse wavelength will affect the damage characteristics of optical elements with different degrees of contamination, we compare the extent of damage on optical glass between nanosecond pulsed laser of 1064 and 355 nm wavelength, respectively, and reach the following conclusions: the surface quality of clean optical elements determines its own anti-laser damage capability; the damage probability of optical sample caused by ultraviolet radiation-induced organic contamination is much higher than the infrared radiation-induced one; and contaminated metal particles can lower damage threshold of optical elements by 2–3 times.