Reinforced concrete(RC) stub columns with sustained pre load were heated and cooled using a specially built electrical furnace. The test focused on the effect of cooling method on the axial deformations, residual load bearing capacity, axial stiffness as well as ductility of fire damaged RC stub columns with sustained pre loads. The test results show that specimens with sustained pre load after exposure to high temperatures suffer remarkable residual compression deformations. The sustained pre load has significant effects on the residual load bearing capacity, axial stiffness and ductility. Cooling method has significant effect on the mechanical behaviors of RC columns after exposure to high temperatures. The effect of cooling by water is more significant than that of other cooling methods.