Abstract: Cerium formate after the reaction of cerium nitrate with formic acid was used as raw material for calcination. The calcined products were characterized under different conditions, and the particle size, specific surface area, morphology, carbon content, nitrogen content and ratio of oxygen to cerium(abbreviated as O/Ce ratio) of the products were analyzed. The results show that the particle size and morphology after calcination are related to those before calcination. Cerium formate particles prepared by the reaction of 16 mol/L formic acid with cerium nitrate are agglomerates with rodlike structure before calcination. After calcination, the morphology remains unchanged and the particle size decreases slightly, and a large number of fine particles less than 0-100 μm are produced when the calcination temperature is higher than 700 ℃. While cerium formate particles prepared by the reaction of 20 mol/L formic acid with cerium nitrate are agglomerates close to spheres before calcination, and the morphology remains the same after calcination, but a large number of fine particles less than 0-100 μm are produced after calcination. The decrease of the specific surface area is caused by the decrease of the pore structure. With the increase of the calcination temperature, the crystal structure is rearranged and the defects in the lattice are reduced, resulting in the continuous reduction of pore structure. The C and N contents of the particles after calcination are mainly related to the calcination temperature. Increasing the calcination temperature can effectively reduce the C and N contents. The calcination time has little effect on the C and N contents. The crystal structure of cerium dioxide is stable, and the O/Ce ratio is basically maintained in the range of 2.000±0.010. Finally, for the two kinds of calcination processes of cerium formate, the calcination temperature is 700 ℃, the calcination time is 1 h, and sufficient amount of air or oxygen is introduced during the calcination.