The effect of different step time on the liquid phase separation process and macroscopic morphology of Al-60 wt% Bi immiscible alloys were investigated by pulsated orifice ejection method (POEM). The results show that the decrease of the step time will accelerate the solidification and growth of the minor-phase globule in the liquid phase separation process, which will have a significant effect on the macroscopic morphology after solidification. The Al-60 wt% Bi core–shell structure particles with Al as the core and Bi as the shell were successfully prepared when the step time was 100 μs. In the same experiment, Al-60 wt% Bi core–shell structure particles with Bi as the core and Al as the shell at a step time of 50 μs were successfully prepared. The same particle size and the same overheat of Al-60wt.%Bi particles with reversed core and shell composition were achieved under containerless solidification conditions.