The behavior of reinforced self compacting concrete filled circular steel tube (RCFST) columns under seismic load was investigated by testing 1 concrete filled circular steel tube (CFST) column and 7 RCFST columns which were subjected to a constant axial loading and a cyclic lateral loading. The effects of the reinforcement ratio, the axial loading level and the steel ratio on the strength, ductility and energy dissipation of the RCFST columns were studied. The experimental results indicate that the hysteretic curves of RCFST columns were plump, and they demonstrated good seismic performance.In the following loading periods, the longitudinal reinforcement of RCFST columns yield, and their strength was efficiently mobilized. RCFST columns display an obvious increase in the strength, ductility and energy dissipation with the increase of reinforcement ratio. The effects of the axial loading level and the steel ratio on the seismic performance of RCFST column were similar to CFST column.