This paper reports stress-strain-electric resistance experiments for diabase, limestone and marble containing NaCl solution during the whole process of uniaxial compression. We obtained the complete testing data for the stress-strain curve and the associated electrical resistance-strain curve. The change caused by internal cracking of the rock causes the corresponding variation of rock electrical resistance. There is a minimum value for all the electric resistance-strain curves, corresponding to the cracking stress σ c or the initial cohesion c i . Based on the experimental results and stochastic property analyses of the rock fracture variation, we put forward a group of state equations for rock in sections to express the characteristics of rock during the whole process of uniaxial compression. The three variables, stress, strain and electrical resistance, together with data-fitted parameters, α 1 ,α 2 and β, are contained in the equations. The equations are used to express the inelastic response which intensifies with the propagation of cracking.