The invention relates to an installation method of insulation boards used for an assembly type refrigeration house. The installation method comprises the following steps of (1) carrying out horizontal line laying and positioning; (2) paving waterproof coiled materials; (3) installing a locating slot; (4) hoisting the insulation boards; and (5) fixing the insulation boards through pressure plates. According to the invention, good seal between the ground base and the insulation boards is achieved, bending deformation, of the insulation boards, generated during the hoisting process can be avoided, and installation and splicing requirements can be satisfied; labor intensity for splicing insulation boards is low, the width of the joint between the insulation boards can be up to the standard easily, and the air impermeability, the moisture-proof performance and the waterproof performance of the refrigeration house are good.