Abstract: The solid solution Ce<SUB<1-x</SUB<Zr<SUB<x</SUB<O<SUB<2</SUB< were successfully synthesized by a modified polymer-network gel process at low temperature. In the ranges of 0≤x≤0.6 and 0.7≤x≤0.9, the solid solutions posses a cubic and a tetragonal phase structure respectively. As for x=1.0, the product is composed of tetragonal and monoclinic phases. The analysis with transmission electron microscopy （TEM） shows that the mean grain size of the solid solutions is within 10-20 nm. The calculated results indicate that the unit cell volume present a linear contraction with the increase of Zr contents. It can be inferred from the results of differential scanning calorimetry （DSC） and XRD that within the scope of 0≤x≤0.9, the crystal symmetry of Ce<SUB<1-x</SUB<Zr<SUB<x</SUB<O<SUB<2</SUB< remains stable between 323 K and 1 273 K.