A theory analysis was presented for the cutting fluid mist formation mechanisms,and the influencing factors on the cutting fluid mists formation were studied by relevant experiments.Experiments were conducted on the enclosed lathe,and the metal cutting fluid was supplied by pouring with the oil supply system of the lathe.A particle diameter measuring device was installed in the dense regions that cutting fluid mists were produced.The distribution of the cutting fluid droplets and the single droplets shape contour could be precise scanned by the Confocal Microscope,and the distribution of droplets and mean diameter size could be calculated through the computer.The effect of the influencing factors on the cutting fluid mist concentration and the mean diameter was investigated by controlling the spindle speed and cutting fluid flow rate respectively.The experimental results show that the cutting fluid mists characteristics is affected significantly by the spindle speed and cutting fluid flow rate in the machining process.The mean diameter of cutting fluid mists is reduced,and the concentration of droplets is increased along with the increasing of spindle speed.The mean diameter and the concentration of cutting fluid mists are increased along with the increasing of cutting fluid flow rate.