The invention relates to an operating method of a converter for smelting low-phosphorus steel by utilizing limestone, which belongs to the technical field of the smelting of the converter. The operating method comprises the following steps: loading raw materials into the converter, wherein the raw materials include molten iron, waste steel and limestone; adding the limestone in three batches by virtue of an overhead bunker, wherein the limestone is adopted as the converter auxiliary material to completely substitute active lime; by adopting slag-remaining operation and double-slag operation as a converting way, controlling the final temperature at 1620 to 1660 DEG C, wherein a final point C is 0.03 to 0.04 by weight percent, and a final point P can reach 0.008 to 0.012 by weight percent. The phosphorus of the molten steel finished product is less than or equal to 0.015 by weight percent. The operating method has the advantages that not only can the carbon emission and dust pollution caused by the combustion of limestone in a sleeve kiln be effectively reduced, but also the auxiliary material cost of the converter also can be effectively reduced. Meanwhile, a purpose for smelting high-quality steel by adopting low-cost auxiliary material can be realized.