Abstract: Spherical GH3536 alloy powders were prepared by vacuum induction-melting gas atomization method at the different atomization pressures (7, 8, 9 MPa). The region below the nozzle was numerically simulated by multiphase flow model and discrete phase model, and the primary and secondary atomization processes at the different atomization pressures were reproduced. In the results, the flow velocity and stagnation pressure in the recirculation zone increase with the increase of atomization pressure. With the increase of atomization pressure, the powder particle size decreases continuously. The simulation results are similar with the experimental results, verifying the reliability of the atomization model. The increase of atomization pressure can increase the yield of fine powders, but the decrease of particle size and the change of particle morphology may directly affect the powder flowability. The powders prepared at the atomization pressure of 8 MPa show the best flowability and the optimum apparent density, which are 14.34 (s·50g⁻¹) and 4.728 g·cm⁻³, respectively.