Guide rails of a serried shelf comprise a base of guide rails and guide rails installed on ground base and mutually fixedly connected together, wherein the base section of the base of guide rails is U-shaped, the ends at both sides are respectively inwards bended to form two hems, a long groove is formed between the two hems, and the guide rails are positioned in the long groove and is fixedly connected with the bottom face of the base of guide rails. The guide rails are characterized in that the bottom face of the base of guide rails is further provided with small holes respectively abutted upon both sides of the guide rails, and the small hole is internally provided with a pressure-expandable plug bolt assembly for locating the guide rails. Compared with the existing technology, in the invention, bolts for fixing the base of guide rails are installed at both side abutted upon the guide rail so that the tension arm between the bolts and the guide rails becomes smaller; the compressing structure of the base of guide rails is reasonable, the pressure effect is good, and the guide rails are easily adjusted on a same horizontal surface, thereby being capable of improving the installation accuracy of the guide rails, and ensuring that roller wheels roll on the guide rails safely and steady.