Lightweight mullite bricks are made of high-quality high-purity refractory materials, according to the required specific gravity of the product, organic composite fillers are added, vacuum extruded and sintered at high temperature to form lightweight mullite products. With its light weight and excellent thermal insulation performance, lightweight mullite bricks are widely used in hot surface refractory linings or insulation layers of various thermal equipment, creating conditions for improving the energy utilization rate of equipment.