The utility model discloses a rotary shear blade seat and belongs to the technical field of metallurgical steel rolling equipment. The rotary shear blade seat comprises a shear blade, a press block, a shear blade seat body, two shear blade shafts and a bolt, wherein the two shear blade shafts are parallelly arranged on a flying shear body, the shear blade seat is arranged on the peripheries of the shear blade shafts and is of an oval structure, the shear blade shafts are wrapped by the oval structure, shear blades are arranged at two ends of a shear blade seat long shaft of the oval structure, a shear blade is arranged at one end of the shear blade seat long shaft, and two shear blades arranged at the other end of the shear blade seat long shaft side by side. After matching, three shear blades are respectively arranged on the two shear blade shafts and are symmetrically arranged along a central line between the two shear blade shafts. The rotary shear blade seat can adapt to high shear speed, and shear efficiency can be improved. In addition, a steel piling accident can be quickly handled, normal production operation is ensured, production efficiency is improved, and the rotary shear blade seat has good practicability.