The deformed steel bar quick fastening device comprises a bottom plate, a motor, a driving gear, a driven gear and a handle, and the driven gear is meshed with the driving gear; the device is characterized in that annular guide grooves are formed in the two side faces of the driven gear, U-shaped supports fixed to the bottom plate are arranged on the two sides of the driving gear, and guide rods extending into the guide grooves are fixed to the U-shaped supports; an inner cavity is formed in the center of the driven gear, at least three clamping columns for clamping deformed steel bars are arranged in the inner cavity, and the clamping columns are fixed to the driven gear. The utility model discloses a quick fastening device for deformed steel bars. When in use, the driven gear is clampedon the deformed steel bar through the clamping column; the deformed steel bar can be screwed into the sleeve connected with the threaded rod by starting the motor, the screwing-in torque of the deformed steel bar meets the design requirement, the defect that connection is not standard due to insufficient torque or too large torque in the prior art is overcome, the construction efficiency is improved, the labor intensity is reduced, the connection quality is guaranteed, and the beneficial effects are remarkable.