Abstract: An earthquake-resistant strengthening structure for building column structures, includes: a plurality of strengthening plates which are made of fiber sheet, are coupled by a concavo-convex structure in a vertical direction and are coupled by a sliding coupler in a horizontal direction; and mortar which strengthens a coupling between the strengthening plates and adheres the strengthening plates to an earthquake-resistant object. The earthquake-resistant strengthening structure is light, can be easily coupled or assembled, and provides a large binding force and tensile force by structural engagement between pieces of the strengthening plates and fusion of bonding materials. In addition, since the strengthening plates are made of glass fiber or carbon fiber, it is possible to provide an optimal earthquake-resistant strengthening structure having high durability, flexibility and strength with no corrosion.