Optical coatings were fabricated by ion assisted deposition technology based on the largest platform of ZZS3600 high vacuum coating machine. Properties of the deposited films as well as thickness uniformity were researched. The familiar optics as Ta₂O₅ and SiO₂ were produced by the ion bombardment of MARK Ⅱ ion sources. Several properties related with the optical coatings were analyzed. It suggests that great improvement achieved of the coating structure and properties of the deposited coatings under the condition that the distance between the substrate and the evaporation sources are extremely large. Based on the geometric configurations of the platform, the coating uniformity research of planetary system and single axis coating system were performed, respectively. The thickness nonuniformity is better than 0.4% without mask under the planetary system. As for single axis system, the thickness nonuniformity can be obtained less than 0.6%. High-quality large optical coatings can be acquired with the aid of double ion sources.