The structure of the standard figure-eight self-supporting central tube optical cable is that single-mode or multi-mode optical fibers are sheathed in a loose tube made of high modulus plastic, and the tube is filled with a water-blocking compound. The center of the cable core is the loose tube. The loose tube is coated with plastic (wrinkle) steel tape longitudinally. The water blocking tape between the steel tape and the loose tube ensures the compactness of the optical cable and the longitudinal water blocking and is placed parallel to the steel strand. Simultaneously squeeze the figure 8 sheath into a cable.