Abstract: The effects of the radio-frequency (RF) antenna and the structure of the discharge chamber with a diameter of 60 mm on the distribution of argon ions were studied by numerical simulation. The results show that the average density of argon ions and its radial uniformity of plasma are effectively improved by using an RF antenna with non-uniform turn spacing compared with those by using an antenna with a uniformly wound coil. With the increase of the height of the discharge chamber, the average argon ion density increases first and then decreases, and reaches the maximum value when the discharge chamber height is 38 mm. Although the use of a stepped dielectric window can improve the argon ion density, it also increases the risk of it being sputtered. The simulation results were applied to the development of the ion source experimental device, and a stable extraction of a 0.24 mA argon ion beam was obtained.