Abstract: Method of three-electrode resistivity is provided for prospecting underground structure and aquifers.It is on the basis of the characteristics of the electric field of point source having a ball symmetry in homogeneous medium and of certain electrod spread.By analysing the abnormal electric field and the distinction of electrical para meters between good aquifers and poor aquifers,the water abundance of geological bodies can be qualitatively estimated.Further the direction of abnormal electric field and the distance from the point source can be quantitatively indicated.It is proved that using this method,a great deal of drill projects can be decreased and this is an efficient and economic geophysical method for mine water control.