Abstract: Based on the three-span calculation model and considering the influence of top tower deviation, the new calculation formulas for cable bent are suggested by making use of mechanical and geometrical relationships. Aiming at various applications, corresponding simplified formulas are also proposed. Besides, the regularity of the influence on the cable bent caused by top tower deviation is discussed. The accuracy of the formula has been proved by the engineering application, which can provide a reference for the construction of cable lifting.