The present invention relates to a sputtering target of a multi-component single body, a preparation method thereof, and a method for fabricating a multi-component alloy-based nanostructured thin film using the same. The sputtering target according to the present invention comprises an amorphous or partially crystallized glass-forming alloy system composed of a nitride forming metal element, which is capable of reacting with nitrogen to form a nitride, and a non-nitride forming element which has no or low solid solubility in the nitride forming metal element and does not react with nitrogen or has low reactivity with nitrogen, wherein the nitrogen forming metal element comprises at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Y, Mo, W, Al, and Si, and the non-nitride forming element comprises at least one element selected from Mg, Ca, Sc, Ni, Cu, Ag, In, Sn, La, Au, and Pb.