Abstract: The flow patterns affected by the nozzle structure parameters and the velocity at jet orifice exit inside the nozzle of air jetvortex spinning were investigated by the method of numerical computation.The results show that the negative pressure along the nozzle axis enhances first,and then diminishes along with increasing the jet orifice angle,and the negative pressure is maximal when jet orifice angle is 30 degree.The tangential velocity decreases along with increasing the jet orifice angle,however,the axial velocity increases along with increasing the jet orifice angle.When the velocity at the exit of jet orifice enhances,the greater the tangential and axial and radial velocity,the bigger the negative pressure along the nozzle axis.The outer diameter of the hollow spindle has comparatively small effect on the velocity of airflow inside the nozzle,however,when the outer diameter of the hollow spindle is smaller,the negative pressure along the nozzle axis will become higher.Increasing the distance between the hollow spindle and the entrance of the nozzle,the velocity and the static pressure inside the nozzle diminish and the negative pressure at the entrance of the nozzle increase.