The invention discloses a special clamp and a clamp group for serpentine laying of large-section cables and a laying method. The clamp includes a clamp body, a rotary base, a slider and a guide rail.The clamp body includes a connecting plate, a lower clamp body, an upper clamp body and connecting bolts. After the upper and lower clamp bodies are closed, a cylinder for clamping a cable is formed.The cylinder is provided with bell mouths at both ends. The connecting plate is rotationally connected with the rotary base, the rotary base is fixedly connected with the slider, and the slider and the guide rail form a sliding pair. When the clamp is used to clamp a cable, the 'bell mouth' structures at the ends of the clamp better match the bending degree of the cable during serpentine laying, so that the mechanical damage of the clamp ports to the cable is reduced, and the service life of the cable is prolonged. Through the setting of the rotary base, the position and angle of the clamp canbe quickly adjusted, the torsion stress generated in the laying process of the cable and the thermal mechanical force generated in the running process can be released, and the running reliability ofthe cable is improved. The use of the clamp group improves the efficiency of cable laying.