Provided is a nanocomposite for the catalyst layer of a fuel cell electrode including: a carbon nanofiber; and metal catalyst particles uniformly applied to the surface of the carbon nanofiber, wherein the carbon nanofiber has a surface oxygen content of at least 0.03 calculated by the formula: Oxygen content=[atomic percentage of oxygen/atomic percentage of carbon] using atomic percentages of oxygen and carbon, respectively calculated from an area of an oxygen peak having a binding energy of 524 to 540 eV, an area of a nitrogen peak having a binding energy of 392 to 404 eV, and an area of a carbon peak having a binding energy of 282 to 290 eV in X-ray photoelectron spectroscopy. The nanocomposite according to the present invention has high surface oxygen content and has metal catalyst nano particles densely and uniformly distributed on the outer wall of the carbon fibers, thereby having high electrochemical efficiency. Thus, efficiency of fuel cells can be improved using the nanocomposite.