Drill bit of full-casing rotary drilling machine

The utility model provides a drill bit of a full-casing rotary drilling machine, which comprises a drill bit main body, a clamping groove is arranged below the surface of the drill bit main body, a second fixing hole is arranged on the peripheral side surface of the clamping groove, and a first fixing hole is arranged on the surface of the drill bit main body. The drill bit is replaced into a sectional type structure, the drill bit can be fixed through the connecting assembly, sectional combination is achieved, the drill bit on a drilling machine does not need to be directly replaced, and only another section of drill bit needs to be connected to the bottom of the drill bit. The top end of one drill bit body is connected to the outer side of a clamping groove of the upper drill bit body in a sleeving mode and then adjusted, a first fixing hole and a second fixing hole are aligned, then a first fixing plate and a second fixing plate in the connecting assembly are tightly attached to the inner side and the oute