The utility model discloses a duct type screw advancing device under water, the device includes screw and driving system two parts, driving system includes the shell, a stator, rotor and tip head, therotor is a hollow cylinder structure, its inner wall forms the tube -shape duct, the screw includes the paddle, its paddle is the continuous blade of a slice crescent, distribute in the tube -shape duct with the winding of spiral mode, at the duct axis direction, the paddle root is arranged according to the helix on the duct inner wall, in the vertical axis direction, the same spiral in paddle blade surface changes, its inward flange is at paddle mesopore of duct center formation, paddle mesopore and the coaxial setting of rotor. The utility model discloses rotor among duct type screw and thedriving system combines as an organic wholely, makes its formation have rotor structure and propeller arrangement's duct type screw concurrently, and the the device directness turns into kinetic energy under water with the electric energy, has reduced the energy conversion link, both energy saving, low carbon environmental protection, and simple structure, silence nature are good again.