Abstract: Overall 8 pieces of specimens were experimentally investigated to study the hysteretic behaviors of the concrete filled square CFRP-steel tubular (S-CFRP-CFST) beam-column. The test results indicated that the longitudinal CFRP can provide strengthening effect for the concrete filled square steel tube (S-CFST) effectively, and the load bearing capacity of the specimen is enhanced. Based on the analysis of the experimental results, it shows that the axial compression ratio can enhance the flexural bearing strength of the specimen, also, the steel tube and the CFRP material can work concurrently both in the longitudinal and transverse directions. The computational result indicates that there are some strength degradation for all of the specimens. The axial compression ratio and the strengthening factor of longitudinal CFRP can enhance the stiffness of members, and they can also delay the stiffness degradation. However, the axial compression ratio is beneficial to aseismic behaviors within a certain range.