Disclosed are a device for forming a three-dimensional internally finned pipe based on multiple-blade ploughing and extrusion, and a method for forming a three-dimensional internally finned pipe. The device comprises a machine frame (1), a machine head (3) capable of providing a rotation power, a supporting mechanism (4), an axial feeding mechanism (5) and a cutter assembly for forming inner fins. The machine head, the supporting mechanism and the axial feeding mechanism are axially mounted on the machine frame in sequence. The cutter assembly for forming inner fins is mounted on the axial feeding mechanism. One end of a metal pipe (7) to be machined into the three-dimensional inner fins is clamped on a chunk of a rotary main shaft of the machine head, and the other end thereof is placed on the supporting mechanism. The rotary main shaft of the machine head provides a rotation power for the metal pipe, and the axial feeding mechanism drives the cutter assembly for forming inner fins to move linearly along an axis of the metal pipe and the cutter assembly for forming inner fins. A three-dimensional and discontinuous internally finned structure machined by using this device and method has a large contact area with a working medium, increasing the turbulent flow effect on the working medium, and has a large heat transfer surface area, increasing the coefficient of heat transfer, thereby effectively improving and strengthening the heat transfer efficiency of a heat pipe.