Approach of micro-scale similar flow field of inert gas was obtained with two numerical methods. It was verified that the flow characteristics of ion thrusters propellant distributor could be better simulated under first-order velocity slip boundary condition by N-S（Navier-Stokes） method. Based on xenon flow features and discharge characteristics of four-ring-cusp discharge chamber

improvement scheme was proposed for decelerating injection velocity and ameliorating circumferential uniformity of propellant. Dual-stage distributor was utilized and extra amounts of orifices were arranged at 45° on both sides. Calculation results demonstrate that after conducting the improvement scheme

circumferential uniformity of xenon has an amelioration of 37% while the speed of flow has a decrease of 32%. Furthermore

experimental results illustrate that ion production cost has dropped from 183W/A to 167W/A at maximum throttle condition

and performance of discharge chamber has improved.