Abstract: A three-dimensional computational fluid dynamics model is developed by software Fluent. The flow structure inside the spinning nozzle of the vortex spinning is simulated with the numbers and orientations of inlet orifices, the gaps between the spinning chamber and the hollow spindle, and the strength of the negative pressure on the outlet of the gap. The relationship between the flowing state and the structure of the vortex spun yarn is also discussed. The results show that the vortex strength and uniformity determined by the numbers and orientations of inlet jet orifices, and the gaps between the spinning nozzle and the hollow spindle. Less angle and gaps lead to stronger vortex and more inlet jet orifices lead more vortex uniformity. The strength of the negative pressure determines the flow axial speed, and which affects the properties of the spun yarn.