Split mast structure, assembling method thereof and drilling machine

The invention discloses a split mast structure, an assembling method thereof and a drilling machine, the mast structure comprises a driving part and a mast main body, the section of the mast main body perpendicular to the length direction is in a square frame shape, and the mast main body comprises a rear-side mast and a rear-side mast located outside the rear-side mast, the front mast is slidably arranged in the length direction of the rear mast through a guide rail sliding groove assembly on the side face; the opposite faces of the front mast and the rear mast are each provided with a containing half groove in the length direction, the driving piece is arranged in a containing groove formed by the two containing half grooves, one end of the driving piece is fixed into the containing half groove of the rear mast, and the other end of the driving piece is connected to the top end of the front mast so as to drive the front mast and the rear mast to move relatively. A working device moving along with the front