The structure of GYTY (metal reinforcement, loose sleeve stranded, polyethylene sheathed communication outdoor optical cable) is that single-mode or multi-mode optical fiber is sheathed in a waterproof composite loose sleeve made of high modulus plastic. The center of the cable core is a metal reinforced core. For some optical cables with a certain number of cores, a layer of polyethylene (PE) is extruded from the metal core. The loose tube (and filling rope) is wound on the central reinforcing core to form a compact round cable core, and the water blocking compound is filled in the gap of the cable core. The cable core is extruded with a polyethylene sheath.