Abstract: In order to develop the removal technology of tritium（T） water vapor from the helium gas as the coolant of high temperature reactors, an experimental hydrogen pump with proton-conducting CaZr_0.9In_0.1O_3-α ceramic material was designed and manufactured. The experiment uses water vapor to simulate tritium water vapor in the helium gas of high temperature reactor. Hydrogen extraction properties from electrolysis about helium with concentration 1 644×10^-6 H₂O vapor and related mechanism were experimentally studied. The results show that the total current, the hydrogen（H₂） concentration extracted by the cathode and the hydrogen recovery efficiency increased with the increase of the loading voltage.However, the actual hydrogen extraction rate deviated from Faraday’s law, indicating that the current efficiency（the ratio of proton current to total current） or proton migration number decreased with the increase of hydrogen extraction rate. The analyzed reasons for the decrease of current efficiency are that factors leading to the reduction of current efficiency include not only the electron hole current of defect equilibrium reaction, but also the reduction of electrode reaction kinetics. Based on this research work, electrodes that promote the outward diffusion of oxygen（O₂） from the anode electrolyte interface can be developed to effectively suppress the electron hole current and improve the proton current efficiency. This study accumulates the experimental basis for the high-temperature proton conductor ceramics applied for the removal of tritium water vapor from the helium gas of high temperature reactor.