Abstract: Under stretching, bending and many other mechanical loading forms, flexible electronics products would inevitably be subjected to complex deformation during working, and fatigue has become one of the most important failure modes during long-time working. In order to solve the reliability problem of flexible electronics, an in-situ fatigue testing platform is developed to study bending fatigue damage behavior of flexible electronic. In the process of bending, the relationship between the minimum radius of curvature and extrusion displacement is determined quantitatively by theoretical analysis, the correctness of the conclusion is verified by finite element simulation and experimental data, and the single and fatigue bending experiments are carried out on the samples of flexible electronics. The experimental results show that the lower concentration of silver nanoparticle ink results in silver film with higher porosity and initial electrical resistance. At the same time, the porosity as a defect makes the bending resistance worse. However, the free surface increases as the pore increases, making the vacancies formed during the deformation more easily annihilated. As a result, the fatigue damage evolution of silver thin films is effectively inhibited, which makes the bending fatigue stability higher.