In the field of catalyst support and adsorption, mesoporous petal-like MgAl₂O₄ has attracted much attention because of their large surface area, abundant and accessible catalytic sites and not easy to aggregate. Mesoporous petal-like MgAl₂O₄ was prepared by a molten salt assisted non-hydrolytic sol–gel method with aluminum wire as aluminum source, magnesium powder as magnesium source, absolute ethyl alcohol as a solvent and Na₂MoO₄ as a molten salt, respectively. The effects of heat treatment temperature and soaking time on the phase composition and morphology of petal-like MgAl₂O₄ were investigated by X-ray diffraction and field emission scanning electron microscopy. The microstructure of the petal-like MgAl₂O₄ was determined by transmission electron microscopy (TEM), and the specific surface area and pore volume were measured by N₂ adsorption–desorption analysis. The results show that heat treatment temperature and soaking time both have an influence on the morphology. MgAl₂O₄ prepared has a petal-like morphology with a length of 140–160 nm when the heat treatment temperature and time are 900 ℃ and 8 h. The specific surface area of the prepared MgAl₂O₄ is 76 m²/g. Based on the results by TEM and N₂ adsorption–desorption analysis, the petal-like MgAl₂O₄ exhibits a mesoporous structure. This work paves a promising approach to prepare mesoporous petal-like MgAl₂O₄.