The invention discloses a brush drilling mechanism used for drilling an inverted-T-shaped hole, and relates to the brush drilling mechanism. The brush drilling mechanism comprises a bottom plate, a first supporting base, a second supporting base and a V-shaped pull rod, wherein a power shaft is arranged on the first supporting base; the power shaft passes through one end of the first supporting base, and is equipped with a first eccentric wheel; one end of the V-shaped pull rod is hinged with the first eccentric wheel through a connecting rod; the other end of the V-shaped pull rod is hinged with a clamping plate through a V-shaped pull rod fixed shaft; the right lower part of the bottom plate is equipped with a motor fixed plate; an eccentric motor is fixedly arranged on the motor fixed plate; the output shaft of the eccentric motor is connected with a second eccentric wheel; the second eccentric wheel is fixedly connected with a cam shaft; and the cam shaft is fixedly connected witha swing plate through a connecting plate. The brush drilling mechanism is small in labor intensity of a worker, and further improves efficiency. The invention further discloses a drilling method of the brush drilling mechanism used for drilling the inverted-T-shaped hole.