In this paper, with the methods of bonding steel, CFRP and complex strengthening, four R.C. T-shaped columns are reinforced. The experimental researches of the above four reinforced columns and one not reinforced in the low-cycle repeated loads are completed. Carrying capacity, energy dissipation, ductility and other characteristics of the T-shaped columns are studied. The results show that: the flexural bearing capacity of the T-shaped columns reinforced with bonded steel is substantially increased; the ductility of the T-shaped columns reinforced with CFRP is substantially increased too; the bearing capacity, ductility and energy dissipation of the T-shaped columns reinforced with complex method are increased synchronously.