Abstract: This paper describes the characteristics of the SU-10 deep well. By analysing the change of water level in the well with reference to earth tide, atmospheric pressure and rainfall, it can be shown that because of the particular well location on the geological structure, the unusual hydrogeological condition, deep burial of the water-bearing stratum of high elastic modulus, porosity and compressibility, its low attenuation constant, high permeability coefficient, good confinement condition and finally less disturbing factors, the water well is quite sensitive to small stress-strain variations.Such a system consisting of a water well and a water bearing horizon behaves as a stress-strain measuring device of high magnification buried at certain depth. It may be significant for the study of the process of development of the earthquake source and its prediction.