This paper describes the structure and performances of Diamond-Like Carbon (DLC) films and introduces the film damage testing principle and methods. It also compares the different deposition techniques of DLC film laser induced damage threshold (LIDT), highlighting the influence of external electric field on the DLC film's LIDT. The photoelectron produced by the excitation of laser and the free electron in DLC film will perform a speedy movement, it indirectly decreases some part of the laser-irradiated area energy density, slows down the DLC film's graphitizing process and consequently improves its anti-laser damage ability.