Abstract: In this paper the differetial equations of the re.spvjnse of the well aquifer systems to seismic waves in the condition of the variation of the well radius are given.It is considered that the variation of the well radius corresponds to a change of the effective height of the well water to affect the natural vibration period of the well aquifer systems.When the total height of the well water column is constance,the more the times of the variation of the well radius is the larger the coefficient of the variation of the well radius is,the larger are the amplification of the response amplitude of the well lever and the natural vibration period of the systems.Using this theory,the response of a well to seismic wave will be better by means of change of its well radicus.