The connection joints of the upper and lower structures of exposed rigid box columns are the key to the seismic design of RC frame light steel storey adding hybrid structures. The low cycle repeated loading tests were carried out on two exposed rigid box column hybrid joints with I-shaped and box shaped upper columns, respectively. The failure mode, hysteresis curve, skeleton curve, strength degradation, stiffness degradation and energy dissipation capacity of the joints were compared and analyzed And compared with the full welding of the inner diaphragm, the finite element model of the joint under the two conditions is established, the stress and deformation of the steel joint are compared and analyzed, and the safety of the joint is evaluated for reference in engineering design and construction under similar conditions.