This paper comprehensively reviews the research progress on mechanical and electrical properties of silicon-based ultrathin flexible chips under uniaxial bending stress, including the bending test methods and the formulas for stress calculation, the bending stress induced effects on the responses of devices and cell circuits, as well as the device modelling strategies in considering bending stress effects. Bending stress can induce variations in critical electrical parameters such as mobility, threshold voltage and drain current of MOSFET, and the variation rate is closely related to the magnitude and direction of the applied stress. By combining the mathematical relations of varied electrical parameters and stress with the conventional device models, the new compact models suitable for flexible and bendable devices can be obtained, which enable the next generation computer-aided-design tools to meet the design needs of high-performance flexible chips in the future.