The invention discloses a method for calculating creep deformation of a lead in a tension pay-off process. The method is suitable for calculating the creep deformation of the whole section of lead during construction of an overhead transmission line. The lead starts to generate creep after being dragged from a tension pulley; in the whole pay-off process, stretching times at different positions of the lead are different, and the creep deformation of the whole section of lead is often difficult to measure. The invention provides a calculating method for the creep deformation of the whole section of lead based on an integral principle according to a lead creep rate equation, tension pay-off speed and pay-off time; the creep deformation of the lead in the pay-off process is accurately calculated and a feasible path for developing follow-up work is provided. The method disclosed by the invention can be applied to the fields such as extra-high voltage transmission line construction, open-wire transmission line engineering construction, measurement and control technology and instrumentation, and the like.