The rock-breaking principle of the rotary barrel drill is to form a broken ring by alternating inner and outer roller bit, then break rocks through extrusion, shearing and impact. Finally, break the rock core in the middle of the barrel bit by oscillating the barrel bit, and form the holes required for the construction after the rock core is taken out. It is mainly used in the pile foundation construction of municipal bridges and buildings. The single roller bit is used as an accessory, which is installed on the barrel drill alternately. The product adopts a large-diameter bearing structure combined with high-saturation nitrile rubber material of excellent performance, greatly improving the bearing capacity and sealing reliability of the bearing, effectively extending the service life of the drill bit under high drilling pressure and high rotational speed conditions. At the same time, the optimized cutting structure improves the drilling efficiency and bottomhole stability of the roller bit. The product can be applied to various rock formation from strongly weathered rock to slightly weathered rock.