Disclosed are a solid oxide fuel cell including: a) an anode support; b) a solid electrolyte layer formed on the anode support; and c) a nanostructure composite cathode layer formed on the solid electrolyte layer, wherein the nanostructure composite cathode layer includes an electrode material and an electrolyte material mixed in molecular scale, which do not react with each other or dissolve each other to form a single material, and a method for fabricating the same. The fuel cell is operable at low temperature and has high performance and superior stability.