The invention discloses a longitudinal wrapping device of an optical cable. The wrapping device is composed of a pedestal; a guide slot is formed in the upper end of the pedestal; a guide rod is arranged in the guide slot; a plurality of molding pieces sleeve the guide rod and are connected with the guide rod movably; and a plurality of lock holes are formed in the guide rod at equal intervals. Locking units corresponding to the lock holes are arranged at the side walls of the molding pieces; and rollers are connected the lower ends of the molding pieces in a rotating manner and are abutted against the inner wall of the guide slot. Device cavities are formed in the middle of the molding pieces; buffer devices are arranged at the bottoms inside the device cavities; and a fixed support is fixedly connected to one end, far away from the bottom inside each device cavity, of each buffer device. The longitudinal wrapping device having a simple structure is operated simply; non-metal reinforced belt forming is realized conveniently; and stable moulding of the non-metal reinforced belt at the reinforced belt moulding piece is realized and thus the cable core is coated well, so that the product quality is improved.