Abstract: The technique to fabricate a doublelayer broadband antireflective (AR) film by sol-gel spin-coating process for high power lasers was investigated. The double-layer film was composed of a single SiO2 AR coating with reflective index about 13 and silicone coating with reflective index about 1.4. The experimental result showed, when the physical thickness of silicone film and SiO2 AR film were 112nm and 125nm respectively, the doublelayer AR film can be developed with transmission greater than 99% at the waveband range from 430nm to 800nm, which can meet the optical quality of shield glass for the prototype of ShenguangIII facility.