The invention relates to an 8-shaped optical cable longitudinal forming die and aims to simplify the optical cable production technology and reduce production cost of an optical cable. The 8-shaped optical cable longitudinal forming die comprises an extruding machine head, the middle portion of the extruding machine head is provided with a step hole, the step hole comprises a left step hole portion and a right step hole portion, the extruding machine head is internally provided with an inner die, the right end face of the inner die is provided with two die holes which are parallel axially, the left end of the inner die is detachably arranged in the left step hole portion, the right step hole portion is internally provided with an outer die in matching with the inner die, the side face of the extruding machine head is provided with a glue injection channel, the glue injection channel is communicated with a gap between the outer die and the inner die, the left side face of the extruding machine head is provided with a fixing board, a longitudinal forming die is fixedly mounted on a mounting rack, a left end of a pipe is fixedly mounted on the mounting rack, the right end of the pipe respectively penetrates through a through hole on the fixing board, the die holes of the inner die and stretches into an inner chamber of the outer die, and a central axis of a forming outlet of the longitudinal forming die and a central axis of the pipe are on one straight line.