MgAl2O4 spinel precursor was prepared by a novel method combining a sol-gel process with the "traditional" precipitation process. The thermal decomposition and phase development of the precursor were analyzed, and the degree of agglomeration of the calcined powder was assessed by determining its particle size and crystal size. The optimum calcination temperature was determined based on the variation of specific surface areas, crystal size, and particle size. Completely crystallized ultrafine spinel powder (d(50)=600 nm, specific surface area=105 m(2)/g) was obtained after calcination at 900 degrees C.