The invention discloses a large-diameter foundation bolt used for installing a power transmission tower. The large-diameter foundation bolt is made of fiber reinforced composite materials and comprises a lower portion buried in a concrete foundation and an upper portion exposed out of the concrete foundation. Rib strips are arranged on the part, at the lower portion of the foundation bolt, of a bolt rod and threads for connecting a nut is arranged on the part, at the upper portion of the foundation bolt, of the bolt rod. The foundation bolt made of the fiber reinforced composite materials (FRP) replaces a metal product, meanwhile, the reasonable rib stripe mode is designed to solve the problem that the durability of a structure is insufficient due to the fact that the structure is corroded in complex environment is solved, and anchoring force and bond strength are high.