Abstract: Hollow cathode’s lifetime is one of the key factors restricting ion thruster’s lifetime and reliability, and insert depletion is the key factor restricting hollow cathode’s lifetime and reliability. In the previous work, an insert consumption model and lifetime prediction method under rated emission current are established. Based on that model, this paper proposes an insert lifetime extension model, in which the emitter further consumes the high-temperature region around the downstream top area. Hollow cathode’s lifetime is predicted based on the new model and under insert depletion failure mode, and the Weibull distribution method is used to give the quantitative evaluation of hollow cathode reliability. Compared with the basic model, the lifetime and reliability of the hollow cathode in the extended model were significantly improved. And the temperature distribution of the emitter plays an important role.