Abstract: Forage resources in animal industry are relatively scarce, and to curb grassland degradation, artificial cultivation forage has been gradually promoted on a large scale．Among them, hydroponic forage has become an emerging cultivation method due to its short growth cycle and higher yield than traditional forage planting methods．However, at present, hydroponic forage cultivation mostly uses simple cultivation racks, and cultivation process needs manual participation, with low productivity．In view of above problems, an automatic three-dimensional forage cultivation device based on double plus conveyor chain was designed, which was mainly composed of cultivation rack system, gantry lifting system, double plus conveyor chain system, irrigation system, and electric control system．It could automatically realize forage cultivation trays lifting and conveying, efficiently complete three-dimensional planting process of forage, and daily yield of forage could reach 8.3 t．This device has greatly solved traditional hydroponic forage time-consuming and laborious problems, improved cultivation efficiency, and provided a reference for design and transformation of automatic three-dimensional forage cultivation devices．