Abstract: First, using uniaxial compression experiment to the borehole cores of body strain meters in Jiangsu, based on the stress strain curve and characteristics of deformation to obtain the mechanical properties of strain meters borehole core quantitatively. Second, using analysis method to calculate coupling coefficient of the plane strain so as to obtain the relationship between coupling coefficient of the plane strain and the mechanical properties. We observe the effects between coupling coefficient of the plane strain and the uniaxial compressive strength and elastic modulus. The results show that the elastic modulus of borehole has obvious influence on coupling coefficient of the plane strain, and with the increase of coupling coefficient of the plane strain, the elastic modulus of rock increase in linear, and the two have a good correlation. The main factor of the mechanical properties of borehole leads to the great difference of coupling coefficient of the plane strain for borehole strain.