Micro-expanded mullite-bonded alumina hollow sphere bricks are prepared at 1 460 ℃ in tunnel kiln, with 0.2~3 mm alumina bubbles and ≤0.044 mm fused white corundum powder as main raw materials and adding different silicon sources into the powders.Mullite forms in the substrate of the brick, and the reaction expansion solves the products shrinkage problem in high-temperature environment for a long time and improves the high-temperature performance of the products.The experimental results show that by adding 15% silicon source C and after being heated at 1 460 ℃ for 35 h, the apparent porosity of the products is 57.7%, the bulk density is 1.49 g/cm3, the refractoriness under load at 0.1 MPa is T0.6>1 700 ℃, and the permanent change in dimension on heating is +0.14% at 1 600 ℃ for 2 h.