Optical damage of several kinds of infrared window materials with 1.06 μm and 0.5106 μm high repetitive laser pulses irradiation has been studied. Mechannism of laser damage is considered as laser induced defect development accumulation process. We first recommend a concept of an absorber and establish a simple model to verify this process. To increase resistance of infrared window materials to the repetitive laser pulses damage, a laser pre irradiation technique is used.