The CaZr0.9In0.1O3-δ can be used as solid electrolyte material for high temperature hydrogen sensors. In this paper, thermogravimetric–differential thermal analysis and X-ray diffractometer analysis were employed to investigate the calcination temperature dependence of fabricating this material. The results show that CaZrO3 matrix phase can be synthesized directly by CaO and ZrO2 at 1000 °C or stepwise by intermediate oxide CaZr4O9 at higher temperatures between 1000 °C and 1200 °C during solid-state reaction process. Doping of indium into CaZrO3 occurs in the temperature range of 1200 °C–1400 °C. With calcination temperature exceeding 1400 °C, no obvious improvement of doping occurs. Even a sharp deterioration of doping effect happens with a temperature of 1550 °C. The CaZr0.9In0.1O3-δ electrolyte powders with a main phase purity of 98.75% were synthesized at 1400 °C for 10 h. The electrolyte tubes with a relative density of 96.8% and a homogeneous crystal size between 2 μm and 3 μm are fabricated out. Hydrogen sensor assembled with the electrolyte tube exhibits good hydrogen sensing performance obeying the Nernst law at 700 °C–800 °C.