Abstract: Spherical cerium carbonate［Ce₂（CO₃）₃］ particles were prepared by gas phase diffusion process through adding sodium polystyrene sulfonate（PSS）.Scanning electron microscope （SEM），X-ray diffraction（XRD），and Fourier transform infrared spectroscopy（FT-IR） were used to characterize the products. Results showed that PSS was able to change the morphology of cerium carbonate；when the mass concentration of PSS was 0.50 g/L and the concentration of Ce（NO₃）₃ was 0.07 mol/L，uniformly dispersed spherical Ce₂（CO₃）₃ particles with particle size of about 3 μm were obtained.At the same time，preliminary diseussion was also made on the mechanism of morphology control.

Key words: gaseous phase diffusion process, sodium polystyrene sulfonate, cerium carbonate