Gas atomization is the most widely used and mature technology to prepare spherical titanium alloy powders. The formation process of the powders, especially the breakup mechanism, has been revealed by the computational fluid dynamics approach. But for the gas atomization process, metal droplets rapidly solidify and form powders under the forced cooling of high-speed gas flow, which primarily determined the microstructure and properties of the powders. In this study, Fluent software was used to simulate the heat transfer process between the gas flow and the droplet to reveal the rapid solidification process. The results indicated that, for the present atomizer, with the increase of atomization pressure, the maximum gas velocity on the central axis increased from 190 to 290 m·s-1. The solidification rate of titanium alloy droplet reached 103~104 K·s-1 under the action of different gas velocity. With the decrease of droplet size or the increase of gas velocity, the solidification rate increases gradually. In the rapid solidification process, the gas flow leads to the uneven heat transfer on the surface of the droplet, resulting in the heterogeneous solidification process inside the droplet.