Objective To obtain the temperature stability of nanocrystalline 8% yttria stabilized zirconia (8YSZ) and prevent the apparent decline of properties of the 8YSZ coating owing to the sintering behavior by investigating the changes of the grain size and the phase composition of the nanocrystalline 8YSZ powders. Methods The nanocrystalline 8YSZ powders with low impurity were prepared by co-precipitation method. Then they were sintered for 3~12 h at 900~1200 ℃ after low temperature calcination. Phase composition and morphology were analyzed by XRD and SEM. The average particle size after heat treatment was calculated by Scherrer formula. Grain growth activation energy was obtained by Arrhenius formula and then the grain growth mechanism was determined. Results Most powders kept amorphous after low temperature calcination pretreatment. After high temperature heat treatment, crystalline state was transformed and the phase of the powders changed to tetragonal. The activation energy was 42.638 kJ/mol at 900~1100 ℃, and 3.849 kJ/mol at 1100~1200 ℃. Conclusion It is primary tetragonal phase after high temperature heat treatment among the nanocrystalline 8YSZ powders which could retain the temperature stability and prevent apparent decline of coating property while the grain growth is controlled by surface diffusion at 900~1200 ℃.