A method for comprehensively analyzing the damage characteristics of optical films is proposed. According to the theory of heat conduction and electron proliferationand, a theoretical model for damage of multilayer dielectric films under laser irradiation is established. Taking HfO₂/SiO₂ multilayer high reflection film as an example, the temperature field, stress field, and free electron number density distribution in the film system under the action of infrared nanosecond pulse laser are calculated, and the damage threshold of the film system under different input conditions is obtained after comprehensive evaluation of its thermal characteristics and electron proliferation characteristics. The results show that the damage characteristics of HfO₂/SiO₂ multilayer dielectric films are affected by the standing wave field. The thermal stress damage effect of HfO₂/SiO₂ multilayer dielectric films is earlier than the thermal melting effect, and the SiO₂ layer in the film is thermal damage, but the film has no field damage. In addition, the damage threshold of the film increases with the increase of laser pulse width.