The invention discloses a butt-welding stirrup and method for improving frame column ductility. A frame column, a frame beam and densified area stirrups distributed on the frame column are involved. Head and tail combination portions of the first stirrup, located at the side of the frame beam, of the densified area stirrups are of a flash butt welding structure, so that the first stirrup forms a butt-welding closed stirrup structure. The distances between the position of the butt-welding closed stirrup structure and the ends of the frame column are 45-50 mm. The flash butt welding structure is located in the middle of the butt-welding closed stirrup structure. After the first stirrup at the end of the frame column forms the butt-welding closed stirrup structure, under the load effect, the stirrup cannot be separated in a bending mode like conventional stirrups, the transverse restraint effect of the closed stirrups to longitudinal ribs and concrete is fully applied, and the ductility and anti-seismic property of the frame column are improved.