Abstract: In order to study the hysteretic behavior of steel frames filled with sandwich composite panels (SCP), low cyclic loading tests on eight full scale one-bay, one storey test specimens were carried out. Six main influential parameters including panel thickness, panel type, panel position, column orientation, beam-to-column connection type and connecting method of panel to steel frame were considered. Seismic behaviors were evaluated according to the experimental phenomena, hysterics loops, skeleton curves, curves of strength degradation, curves of stiffness degradation, ductility index and viscous damping coefficient. Test results show that the failures of panels mainly occur around the embedded parts, but the integrity of the panels is better than the traditional walls. The success of connection between panel and steel frame is especially important to guarantee the mutual work of the two parts. Both increasing the panel thickness and strengthening the connection can improve the seismic behavior of the structure. Finally, seismic design recommendations were presented based on the analysis of ductility index and energy dissipation of the structure.