Abstract: To obtain the optimal matching relationship between the length and width of the discharge channel of the Hall thruster and to improve the thruster performance，a one-dimensional fluid model relying on the LHT-70 Hall thruster developed by the Lanzhou Institute of Physics was used to study the influence of the anode propellant flow rate on specific impulse and thrust，and the rationality of the model was verified by comparing it with the experimental data.On this basis，the effect of the discharge channel aspect ratio α（the ratio of length to width）on the performance of the Hall thruster was studied.The results show that with the increase of the discharge channel aspect ratio，the electron temperature decreases，the electron density increases，the ionization rate increases，and the ion density increases.However，due to the increase in neutral atom density and ion wall loss，the propellant utilization rate decreases.The potential drop at the exit of the discharge channel，the specific impulse，thrust and efficiency first increase and then decrease.It can be seen from the trend of propellant utilization rate，specific impulse，thrust and efficiency changing with the increase of the discharge channel aspect ratio that when the volume and internal radius of the discharge channel are fixed，the length is increased，and the discharge channel aspect ratio is 1.80~2.05，the performance of the Hall thruster reaches the optimum.The results will provide theoretical guidance for the optimal design of Hall thrusters.

Key words: Hall thrusters, discharge channel aspect ratio, discharge characteristics, performance parameters, fluid simulation