Abstract: During tritium transfer from uranium bed to Zr_0.85Ti_0.15Co bed, the effect of helium-3 on the tritium absorption performance of Zr_0.85Ti_0.15Co alloy was studied, and the mechanism of helium-3 influence was analyzed by combining with the Ortman model. The results showed that helium blanketing effect affected the adsorption performance of Zr_0.85Ti_0.15Co alloy significantly, but the blanketing effect could not completely inhibit the tritium absorption reaction, and it could continue to absorb tritium at a low rate until the adsorption was completed. The completion time of tritium absorption was mainly affected by helium-3 concentration when helium-3 concentrations was low, while when the helium concentration was high, it was mainly affected by the initial tritium partial pressure. Helium-3 blanketing process included two steps, that was “bulk flow” and “diffusion flow”, and Ortman model could predict the helium shielding pressure in “bulk flow”.