A method for fabricating a silicon-doped or boron-doped aluminum electrode is revealed. Aluminum target or aluminum paste prepared by selectively doped with silicon and/or boron is arranged at a silicon wafer with a passivation layer by physical deposition or screen printing. Then the doped aluminum layer is melted in linear or dot pattern to pass through the passivation layer and contact with the silicon wafer. Thus contact resistance between an aluminum back electrode and the silicon wafer of crystalline silicon solar cells is reduced and acceptor concentration on a surface layer of the silicon wafer is increased. Therefore the process speed is faster and the energy conversion efficiency of the solar cell is improved.