The invention relates to a gradually-changed trapezoidal bend-torsion member of an internal anchoring cable and a manufacturing method. The manufacturing method comprises the following steps that (1),a final assembly jig frame is arranged, and setting out, discharging and splicing of parts are conducted; (2), wing plates and webs are subjected to pressing forming through a die-free forming machine, and the lower wing plates are temporarily fixed on the final assembly jig frame; (3), reinforcing plates in the positions of transverse stiffened plates, longitudinal stiffened plates and the wingplates are assembled and positioned, and the webs of the two sides are subjected to displacement fitting as well as positioned assembling and fixing; (4), the transverse stiffened plates and the longitudinal stiffened plates are welded to the lower wing plates and the webs; and (5), supporting plates are assembled and positioned, horizontal stiffened plates and inhaul cable plates are assembled and positioned, the segmented upper wing plates are assembled and positioned, and the upper wing plates disconnected by pull locking plates are temporarily assembled and positioned. According to the gradually-changed trapezoidal bend-torsion member of the internal anchoring cable and the manufacturing method, the manufacturing efficiency and accuracy control of the trapezoidal bend-torsion member ofthe internal anchoring cable are greatly improved, the angles of the inhaul cable plates are effectively ensured, forming of the surface of the member is attractive, the manufacturing period of the member is shortened, and the manufacturing cost is saved.