In order to study the laser induction damage threshold (LIDT) of metal Al-protected, single-period and double-period enhanced reflective films under 532nm laser with 5ns pulse width, Comsol software is used for simulation and analysis. The tensile strength (film breaking stress) of SiO2 and Ta2O5 are introduced as the threshold condition in the simulation process, and the damage threshold values of three film systems are 0.318J/cm2, 1.325J/cm2 and 3.382J/cm2 respectively. By building an experimental platform to test the laser damage threshold, the 1-on-1 mode is adopted, and the laser damage point with a probability of 50% is selected as the damage threshold. The results of measured laser power are 0.288J/cm2, 1.232J/cm2 and 3.152J/cm2 respectively, which are close to the simulation results, indicating that the model based on tensile strength analysis is more in consistent with the actual damage, which provides a theoretical basis for the prediction of the threshold value of this kind of film system in practical application.