Aiming at the special application of light source for missile detection and guiding for,by materials choosing,film designing and process parameters optimization,using electron-beam vacuum coating and ion-assisted deposition technique,the anti-reflective film is plated successfully on the optical fiber end whose diameter is 50 μm.By studying the film stress matching and the film fastness when low-temperature coating,and the examples comparison charts and transmittance curves were given before and after fiber end coating.In the system which light source is YAG laser,when the laser′s operating current is 2000 mA,the fiber power is improved by 5% compared with the un-coating fiber;the fiber can withstand the irradiation of laser sources and the poor environmental testing,reaching to the using requirements.