The Al2O3 content of clay heat Clay insulating refractory bricks is generally more than 40%, and the Fe2O3 content is less than 2.0-2.5%. The clinker in the ingredients is 65-85%, and the combined clay is 35-15%. The crushed bonded clay and the finely ground clinker are mixed and milled, and then mixed with the granular clinker to make semi-dry mud, high pressure molding, and sintering at about 1400 ℃, with good performance.