Topological insulators (TIs) are new emerging quantum materials which have bulk insulating gap and surface conducting gapless states. Doped TIs have depicted a large variety of bulk physical properties ranging from magnetic to superconducting behaviors. Here, we show that by transition metal doping, a TI can change into a bulk superconductor. However, angle-resolved photoemission spectroscopy (ARPES) of the doped TI shows its topological surface state is unchanged. Zero resistivity, Meissner effect and heat capacity will be shown to suggest that these transition metal doped TIs could be topological superconductors which have bulk superconducting and Majorana surface conducting states.