The invention discloses a novel anti-falling screw drilling tool. The novel anti-falling screw drilling tool comprises an anti-falling shell, an anti-falling nut and an anti-falling connecting rod, wherein a by-pass valve is connected to the left end of the anti-falling shell in a threaded mode. The by-pass valve comprises a valve body, a valve element, springs and seal rings, wherein a cylindrical passage is arranged in the valve body and communicates with a by-pass opening formed in the side portion of the valve body. The by-pass valve further comprises a shearing pin, a locating sleeve anda steel ball, wherein the valve element is of a cylindrical structure internally provided with a passage, the valve element is mounted in the cylindrical passage in the valve body through the springsand matched with the valve body through the seal rings in a sealing mode, wherein the valve element is further connected in the locating sleeve through the shearing pin and matched with the valve bodythrough the seal rings in a sealing mode. The outer diameter of the steel ball is larger than the inner diameter of the valve element, the right end of the anti-falling shell is connected with a stator of a screw motor in a threaded mode, the left end of the anti-falling connecting rod is connected with the anti-falling nut in a threaded mode and located in the anti-falling shell, and the right end of the anti-falling connecting rod is connected with the stator of the screw motor in a threaded mode and located outside of the anti-falling shell.