Abstract: The ion sputtering intensity of the hollow cathode in the coupling discharge in the ion thruster is different from that in the single experiment,which leads to the difference of its lifetime in the two conditions.There are few related researches because of the difficulties to measure the plasma parameters in the discharge chamber of the ion thruster.Based on this situation,the coupling discharge experiments were carried out with an ion thruster and a hollow cathode.By controlling the variables,the plasma parameters in the discharge chamber were measured by Triple Langmuir Probe under the different conditions of anode current,anode flow rate,magnetic field intensity and sealing degree of discharge chamber.The axial and radial variation trends of electron temperature,electron density and space potential of plasma under various working conditions were obtained.The effect of these working parameters on the lifetime degradation of hollow cathode was analyzed.It provides data basis for the comparison of plasma characteristics and lifetime degradation of hollow cathode under two conditions.