In this paper the dynamic method of measuring the electric charge quantity of oil droplets is explored. Through the analysis of the dynamic process model，equations of the dynamic method for solving the charge quantity of oil droplets are obtained. A program of data processing for measuring the micro-electric charges by dynamic method is designed，which makes the dynamic method applied more easily in teaching. In addition，the analysis enriches the physical connotation of Millikan oil-drop experiment and deeps the understanding of the theoretical knowledge. The exploration results have an important and significant reference to the in-depth understanding of the process of oil-droplet electric charge measurement by the dynamic method.