A precise rotary rod pipe material blanking device with a hydraulic controllable single-piston comprises a rotary blanking cylinder body and a rod pipe material blanking part, adopts rod pipe material sleeves with different inner diameters according to metal rod pipe materials with different diameters and materials and utilizes a hydraulic controllable feeding piston type hammer to perform loading of radial displacement load. By means of the rotary function of the rotary blanking cylinder and the transmission function of a deep groove ball bearing, the radial displacement load can be continuously and evenly loaded on the metal rod pipe materials, so that fatigue cracks can be evenly and stably formed at the bottom of V-shaped grooves of the metal rod pipe materials and can stably expand toward the centers of the metal rod pipe materials until the fatigue cracks break instantly in a non-eccentric mode, and the blanking procedure is finished.. The blanking process is efficient and controllable, and the blanked metal rod pipe materials have the advantages of being high in section quality and geometric accuracy and the like.