Engineering structures such as pipelines usually operate under stressing conditions. When corrosion occurs on the structures in service environments, the stress and corrosion reactions synergistically result in a so-called mechano-electrochemical (M-E) interaction, adversely affecting the structural integrity. In this work, electrochemical corrosion thermodynamics of an X52 pipeline steel under elastic and plastic stresses was developed by investigations of corrosion potential and Kelvin potential as a function of stress in an anaerobic diluted bicarbonate solution and an aerobic concentrated carbonate/bicarbonate solution. Theoretical formula of stress-induced corrosion potential and Kelvin potential shifts were derived in the two environments. Under elastic deformation, the shift of corrosion potential caused by an elastic stress is results primarily mainly resulted from an elastic strain energy and the energy associated with volume change of the steel is negligible. Application of a plastic stress generates a deformation potential due to dislocation multiplication and lattice distortion, increasing corrosion activity of the steel. The stress-induced corrosion potential changes were usually small, within several millivolts. However, the Kelvin potential, which nulls the Volta (outer) potential difference during scanning Kelvin measurement and provides an indicator for corrosion thermodynamics study, shifts much more remarkable when a stress is applied, since it is extremely sensitive to changes of metal surface condition. In the aerobic concentrated carbonate/bicarbonate solution, the steel can be passivated. Application of a plastic stress weakens the stability and thickness of the passive film. Both the substrate steel and the steel passivity play an important role in stress-corrosion interaction of pipeline steel. Terms for the passive film was added to theoretical formulas derived in the anaerobic diluted bicarbonate solution.