The invention discloses a drilling machine for road construction. The drilling machine comprises a machine base and a drilling mechanism arranged above the machine base; an empty groove is formed in the right side surface of the drilling mechanism; a bulge rod with the left side surface fixedly connected with the inner wall of the left side of the empty groove is arranged in the empty groove; a transfer cavity extending leftwards and rightwards is arranged in the left side of the bulge rod; an open groove is formed in the right side surface of the bulge rod; a plate is arranged between the left end of the open groove and the right end of the transfer cavity; a wheel cavity with the right end communicating with the left end of the transfer cavity in the bulge rod is formed in the left side of the drilling mechanism; a rotating wheel is arranged in the wheel cavity; through holes communicating with the empty groove are symmetrically formed in the front inner wall and the back inner wall of the side, opposite to the plate, of the transfer cavity; a first sliding sleeve is arranged outside the bulge rod; a sliding cavity is formed in the right side of the first sliding sleeve; and a sliding stopping block is arranged in the sliding cavity. The drilling machine is simple in structure, convenient to move and carry, capable of realizing drilling and ash absorbing operations, high in safety and good in drilling effect.