Due to serious corrosion of ground water in saline soil area, the durability of pile foundation is seriously reduced in transmission line towers. Prestressed cast-in-place pile, which was reinforced with prestressing tendon in pile body and applied prestress by the post tension method, provides significant improvement in construction durability. Through numerical examples, it is found the additional prestressing tendon can effectively increase pile body crack-control level and reduce material dosage in foundations. The advantage of GFRP guard barrel replacing steel guard barrel are narrated with the reduction of the construction costs and the local workload. The design method of prestressed cast-in-place pile, construction process and manufacture method of prestressed steel cage with tensioning and anchoring constructions control points are recommend in the paper.