Improvement of the thrust weight ratio of gas turbine engine rely on increased engine operating temperature. At present, it is a priority to find new thermal barrier coating ceramic materials with a higher temperature tolerance than the traditional YSZ (Yttria partially stabilized zirconia) material and match thermal expansion coefficient of Ni-based superalloy matrix. A series of ytterbia stabilized hafnia (YbSH) were prepared with hydrothermal nano-powders by solid-state sintering. Effects of the ytterbia on the microstructure, phase stability, and thermal expansion coefficient of the doped hafnia ceramics were investigated. The microstructure and phase stability mechanism of Yb2O3-doped HfO2 powders and ceramics were analyzed by XRD, Raman, and TEM. DSC-TG and TMA were used to test the high temperature phase structure stability and thermal expansion coefficient of cubic phase structure of YbSH ceramics. The results showed that the grain size of the hydrothermal nano-powder was less than 10 nm, with a uniform distribution and a great crystal state. Most of the powers were cuboid and the density of the sintered ceramics can reach more than 95%. Crystallography analysis revealed that the Yb(III) ion distorted the lattice by replacing Hf(IV) ion position which made the space group of HfO2 from monoclinic phase distortion of P21/c to the cubic phase Fmˉ3m. The hafnia gradually lost its monoclinic phase structure with increasing doping amount of ytterbia, once the doping concentration of ytterbia raised up to 12 mol/mol. By expanding cationic network and generating oxygen vacancy, oxygen overcrowding was effectively alleviated. The cubic phase structure showed good stability from room temperature to 1500℃ by high temperature heat treatment and monitoring enthalpy change of YbSH nanopowders and ceramics during heating process. Average thermal expansion coefficients of YbSH ceramics increased with cubic phase content increasing from 6.016×10-6℃-1 to 10.14×10-6℃-1 (from room temperature to 1500℃). The thermal expansion coefficient of YbSH ceramics doped with 20 mol/mol ytterbia can reach 10.5×10-6℃-1 (from 1000℃ to 1200℃), which was 67.22% higher than that of pure hafnia.