The invention relates to an optical fiber drawing method for a large-diameter optical fiber preform rod. The method comprises the following steps: continuously moving the large-diameter optical fiber preform rod downwards to enter an optical fiber drawing furnace through a lifter, heating and drawing to form a finished optical fiber, inputting protective gas into the furnace body through an extension pipe at the furnace bottom, allowing the protective gas to flow upwards, allowing the gas to flow out of a gas outlet of a gas guide disc, and allowing the protective gas input by the gas guide disc and a gas sealing cover to flow out of the gas outlet of the gas guide disc. The method has the advantage that the large-diameter optical fiber preform rod can be drawn to form the optical fiber with stable quality.