Abstract: Numerical simulations were conducted using Ansys Fluent software to model the preparation process of Al_0.5CrFeNi_2.5Si_x (x=0, 0.25, 0.50) high-entropy alloy powders via vacuum induction melting and inert gas atomization (VIGA method).The effects of different atomization pressures at the same silicon content and different silicon contents under the same atomization pressure on the powder particle size distribution were studied. The VOF multiphase flow model coupled with the standard k-epsilon turbulence model, the VOF multiphase flow model coupled with the LES (large eddy simulation) model, and the DPM (discrete phase model) coupled with the TAB (Taylor analogue breakup) model were employed to simulate the single-phase flow field, primary atomization, and secondary atomization processes during gas atomization, respectively. These simulation results were validated by actual experimental methods. The simulation results indicate that in the single-phase gas flow field, an increase atomization pressure causes the expansion wave area to gradually expand, which in turn shifts the Mach disk position continuously downward. As the atomization pressure gradually increases from 4 MPa to 6 MPa, the gas flow velocity continues to increase, with maximum speeds of 693, 704 and 711 m/s respectively. During primary atomization, under different atomization pressure conditions(4, 5, 6 MPa), the disturbance intensity of the gas flow on the liquid film is significantly enhanced and the fragmentation frequency of the liquid film increases remarkably with the increase of atomization pressure, leading to a gradual shortening of the liquid column length of the Al_0.5CrFeNi_2.5Si_0.25 high-entropy alloy melt. When the atomization pressure is maintained at 5 MPa, the liquid film becomes more prone to detachment from the liquid column as the Si content gradually increases, resulting in more significant primary atomization fragmentation, and the liquid column length of the Al_0.5CrFeNi_2.5Si_x(x=0, 0.25, 0.50) melt also gradually shortens. During secondary atomization, the median particle size D₅₀ of the metal powder decreases from 35.30 μm to 32.54 μm with the increase of atomization gas pressure while the umbrella-shaped range of particle descent shows no significant change. Under the same atomization pressure condition, the median particle size D₅₀of Al_0.5CrFeNi_2.5Si_x(x=0, 0.25, 0.50) alloy powder decreases from 34.96 μm to 31.77 μm as the Si content increases, and the umbrella-shaped range of particle descent changes slightly. When the Si content increases from x=0.25 to x=0.50, the decrease in median particle size D₅₀ is more significant. Numerical simulations can effectively reproduce the gas-atomized powder preparation process with a small deviation from the actual results, thus providing theoretical support for the optimization of metal powder preparation technology.