The invention discloses an alumina spinel brick, which comprises the following components of: by weight, 8-12 parts of high-purity brown fused alumina particles of 3-5mm, 30-35 parts of high-purity brown fused alumina particles of 1-3mm, 15-20 parts of fused white corundum particles of less than or equal to 1mm, 10-13 parts of fused white corundum fine powder, 15-18 parts of fused spinel mixed fine powder, 10-12 parts of a composite binder and 4.5-5.4 parts of water. The invention also discloses a preparation method of the above alumina spinel brick. The alumina spinel brick provided by the invention has high refractoriness and high temperature flexural strength, and simultaneously has excellent characteristics such as good thermal shock resistance, corrosion resistance, penetration resistance, anti-stripping performance, low linear change rate and the like, and is especially suitable for petrochemical industrial waste liquid, exhaust gas incinerator, rotary kiln industrial waste incinerator and fusion incinerator inner liner. The manufacturing process is simple and easy to realize.