Building formwork support frame

The utility model relates to a building component, in particular to a building formwork support frame comprising a transverse beam and a vertical beam. The vertical beam is provided with an outer rod and a core rod, the outer rod is provided with a groove, a flanging is arranged at the position of a groove opening, the core rod is just placed in the groove of the outer rod, and an exposed face of the core rod and the flanging of the outer rod are in the same plane. The transverse beam is provided with two parallel beam columns, a bayonet is formed at the right end of each beam column, and a tip which can be just placed in the bayonet is arranged at the left end of each column beam. By the aid of the scheme, the beam columns can be overlapped mutually conveniently to lengthen the transverse beam; the vertical beam is ensured to contact with a formwork in a whole surface manner in the extension process to enable the formwork to be evenly stressed without deformation, an extension range is larger particularly by