Abstract: The study on blending homogeneity and pressureless sintering of the simulated MOX (UO_2-10%CeO_2) fuel powder was carried out. The influences of milling process factors on the blending homogeneity (or coefficient of variation, CV) of the planetary high-energy balled simulated MOX fuel powder and Ce distribution homogeneity (analysized by EPMA method) in the sintered pellet were discussed. A powder blending homogeneity of above 98% (or CV of below 2%) and a good Ce distribution homogeneity in the pellet are achieved with the optimized milling parameter. The main milling mechanism may well be diffusion.