In this paper, LiMn2O4 materials were prepared by a solution combustion synthesis method using acetate salts as raw materials and acetic acid as fuel. The effect of further calcination at 500°C and 600°C on the phase structure and composition were investigated. The composition and phase structure are determined by X-ray diffraction (XRD). XRD results indicated that the main phase of the products was LiMn2O4,and there was a trace amount Mn2O3 impurity in the products prepared at 500°C and 600°C. The impurity Mn2O3 in the products prepared at 500°C is increased with increasing calcination time, but the Mn2O3 in the products prepared at 600°C is decreased. The grain sizes of the products prepared at 500°C and 600°C are increased with increasing calcination time, and the grain sizes of the products prepared at 600°C are larger than these of the products prepared at 500°C. The lattice parameters of the products prepared at 500°C and 600°C are smaller than that of LiMn2O4 with perfect crystal, and the lattice parameters of the products are more close to that of LiMn2O4 with perfect crystal.