Abstract: Aftanas' method is applied to 201pb-201Tl generator and a quantitative formula relating the elution yield to the column load,the radius and the density of hydrous lead ion,etc. ,is induced in the essay. This formula is verified with experiments. This work related the elution yield to the physical and chemical states of Pb2+ and Tl3+under the working condition .investigated the elution mechanism and provided the foundation to the study on increasing elution yield.