Abstract: The law of motion of the dust was studied.After the dust samples were treated by liquid-dispersed,the dust concentration was measured using the filter membrane-weighed method and the particle sizes of the dust were measured by the microscope method.The sample photos were taken by digital camera and further processed by image-processing software for the count,but these two methods were improved in the experiment.The distribution laws of concentration and particle size of the dust were obtained by summarizing and analyzing the data.