Laser damage performance of multilayer films with combined irradiation of 1w and 2w is studied to probe the damage mechanisms during wavelength division. The laser induced damage thresholds (LIDTs) of the samples are obtained and tested with only 2w with various energy densities of lw. Different 1w polarization directions combined with the 2w case are also investigated. The result suggests that 1w can raise the damage probability of multilayer mirrors when two light wavelengths are present simultaneously; the increasing number of sensitive defects for 2w can be related to the decline of the LIDTs of the multilayer mirrors.