The invention provides an extra-large-span saddle-shaped flexible network cable tensioning forming construction method. A step-by-step lifting overall tensioning method is provided to carry out construction, blanking is carried out on hanging cables and annular cables according to the set length, the hanging cables and the annular cables are assembled on the ground, the hanging cables are selected as tensioning cables, the hanging cables are hoisted in batches in a subsection mode, finally the hanging cables are tensioned and mounted in place, and the whole network cable structure is tensioned and formed. The method solves the problem that construction difficulty is large due to annular cable tensioning, and saves the number of construction personnel and mechanical consumption, due to the fact that the dynamic and continuous construction process is divided into construction periods and each hoisting period is statically controllable, construction quality detection is facilitated better, the whole set of brand-new extra-large-span saddle-shaped flexible network structure construction technology is formed, the construction method is small in high-attitude work quantity, the high-attitude work quantity is reduced by more than 60 percent relative to a traditional tensioning hoisting process, a supporting tower and other auxiliary facilities are removed, the construction period is shortened by 50 percent, and the method can be widely applied to flexible network structure construction.