Abstract: The damage threshold can increase 2-3 times through laser conditioning optical component using the subthreshold laser energy. In the process, it will make the optical component produce damage inevitably, if the damage does not affect the optical performance, which is acceptable in principle. In this paper, the S-on-1 LIDT of hafnia silica multilayer high reflective coatings was introduced firstly. Experimentally, the damage process of optical coatings during laser conditioning was studied. At the same time, the laser damage appearance that affected the optical capability and LIDT of coatings was analyzed. The result is, with the film system of G/(HL)11H2L/A, after laser conditioning for the HfO2/SiO2 multilayer HR coatings, the destroyed of outermost SiO2 coating can not affect its spectrum performance. Reversely, the LIDT of coatings is enhanced sharply because removing the nodula in the next HfO2 coating.