Abstract: Magnesia-based refractory materials serve as a critical fundamental material in the clean steel smelting process, providing crucial support for achieving efficient production. In order to improve the thermal shock resistance of traditional periclase-magnesia alumina spinel refractories, lightweightMgO-MgAl₂O₄ refractory materials were prepared using magnesite powder as the raw material and alumina hollow spheres as the pore-forming agent. The effects of the addition amount of alumina hollow spheres and the sintering temperature on the properties of the lightweight refractories were investigated. Theresults indicated thatunder the calcination condition of 1 550 ℃, when the mass fraction of Al₂O₃ hollow spheres added is 20%,the sample exhibited bulk density of 1.67 g/cm³, apparent porosity of 52.70% and cold modulus of rupture of 2.41 MPa. The analysis suggests that the coating of in-situ synthesized magnesium-aluminate spinel particles, derived from the alumina hollow spheres and fine magnesite powder,forms on the surface of the hollow spheres. The coated structure contributes to the improved mechanical strength of the samples. Meanwhile, the Al₂O₃ hollow spheres are introduced into the sample as closed pores, which can impede crack propagation under thermal stress. Furthermore, the incorporation of alumina hollow spheres as a second phase into the magnesia-based refractory system induces thermal mismatch, significantly improving the thermal shock resistance of the material.