The invention discloses a while-drilling adjustable tapered stabilizer comprising a shell, a signal valve, a first piston column, a bevel body, a chute, a rib, a support block, a spring, a second piston column, a connector, a rotation groove and a pin rod; and one side of the interior of the shell is provided with the signal valve. The while-drilling adjustable tapered stabilizer is arranged, thesize of the stabilizer is adjusted, the well inclination control capability of a lower drilling tool is changed, the hole drift angle of a well is accurately controlled, the small diameter state in the drilling process is kept, the blocking phenomenon is avoided, the problems of blockage and clamping during lower drill lifting of the stabilizer are solved, major accidents such as well collapse andblowout caused by suction of pulling supporting blocks are fundamentally eliminated, safety is ensured, and major economic losses are avoided. By means of the while-drilling adjustable tapered stabilizer, simple and quick adjustment can be carried out by starting and stopping pumps simply, so that well inclination can be precisely controlled. In a horizontal section, the size of the stabilizer isadjusted, and the TVD (deep depth) can be accurately controlled.