Abstract: The present invention relates to an assembled sound-muffling thermal insulation board, and more particularly to a thermal insulation board having a surface board provided with plural pyramid bodies capable of greatly reducing the reflected sound wave going thereinto, and a sound-muffling thermal insulation layer mounted on the back face of the surface board, which is made from a styropor material and provided with plural fluffs to prevent convection of outdoor and indoor air with different temperatures whereby the hot air or cold air in an air-conditioned room will not escape and the energy is saved.