Abstract: This paper introduces a prestressed steel jacket (PSJ) strategy to retrofit RC columns with rectangular section for enhanced shear strength and improved ductility. Numerical simulation and cyclic loading test were carried out to evaluate the seismic behavior of the RC columns retrofitted by PSJ, and the transfer mechanism between PSJ and RC columns was analyzed. The examined parameters were shear span, axial compression ratio, steel jacket and prestressing level of PSJ. Based on the results of numerical simulation and cyclic loading test, it was concluded that the shear strength of the retrofitted columns were enhanced effectively and their displacement ductility ratio were improved significantly. In addition, the strengthening effect on seismic behavior was investigated and its applicable range was proposed.