In indoor thermal insulation, the relatively thin rigid polyurethane foam insulation layer can meet the requirements, whether it is on the ground for thermal insulation, or under the floor laying insulation layer, are particularly useful. The rigid polyurethane foam plastic plate with only 20-40mm thickness is enough for the general floor insulation layer; if the ground heating pipeline is to be laid, the special foam or drilling plate can be used. Rigid polyurethane foam can maintain good stability under long-term pressure. When ground heating and temperature rise to 40 degrees, it can maintain the same stability.