The invention discloses a CL thermal insulation system construction method, and belongs to the technical field of building construction. The method includes the steps that the customizing, decomposingand numbering of CL net rack plates is conducted; additional steel bars are mounted on the CL net rack plate; the CL net rack plate is installed, and the CL net rack plate is bound and fixed with fixing steel bars; a plurality of special cushion blocks are installed at the two sides of the CL net rack plate, and water and electricity pipelines are laid; a formwork used for concrete pouring is installed on the CL net rack plate, through-wall bolts are arranged on the formwork, and self-compacting concrete is matched in a trial mode; and self-compacting concrete is poured, the formwork is removed, and the concrete is maintained. According to the CL thermal insulation system construction method, the structure erecting work of a CL heat preservation system can be simply and rapidly completed,the construction process is simplified, cost is reduced, and stability and firmness are achieved; and the in-mold temperature and pouring points are controlled, the special cushion blocks are arranged at certain intervals, and the concrete pouring height difference between the two sides of the heat preservation plate is controlled, so that the situation that the CL net rack plate does not generate lateral displacement is guaranteed, the pouring requirement and pouring quality of the concrete are met, and the construction is safe and efficient.