The invention provides a tunnel supporting drilling robot which comprises a brushless direct current motor for the power source of a drill bit, a gear reducer, a support structure of an overall tunnel supporting robot, namely an improved universal bullseye wheel, a screw sliding table, a rotary motor, a coupler, a photoelectric coded disk feedback system, an electric cabinet and an automatic ejection mechanism, wherein a miniature screw sliding table is adopted for feeding of a drilling device; the power of the screw sliding table is a stepper motor; the screw sliding table is positioned and driven along the axial direction of a tunnel; the rotary motor is positioned along the periphery of the tunnel; the photoelectric coded disk feedback system is used for achieving accurate positioning; the electric cabinet is arranged at the tail part of the overall robot; the automatic ejection mechanism of a wedge block anchor rod is especially designed for achieving automatic insertion of the anchor rod; and various parts are tightly matched to form the tunnel supporting robot. A tunnel supporting drilling structure employing improved universal bullseye wheels arranged at three angles of 120 degrees along the circumference direction of the tunnel is utilized; position close-loop control is adopted; and charged self locking of a stepping driver is utilized, so that the positioning accuracy is high; the structure is simple; and drilling is flexible.