In electrical devices like superconducting motor, generator and SMES, HTS coated conductor (CC) tapes will be subjected to alternating stress or strain during manufacturing and operation. The repeated loading will affect the mechanical integrity and eventually the electrical transport property of CC tapes. Therefore in such applications, electro-mechanical property of CC tapes should be evaluated. In this study, the endurance of an IBAD/EDDC–SmBCO CC tape under high-cycle fatigue loading has been evaluated. Applied maximum stress and fatigue life (S–N) relation was obtained at 77K. The mechanical properties and the critical current, I c , of the sample under fatigue loading were investigated at 77K. Considering the practical operating environment, the effect of the stress ratio R, on the degradation behavior of I c under fatigue loading was also examined.