PVP(polyvinyl pyrrolidone)/［Y(NO3)3+Al(NO3)3+Tb(NO3)3］ noncrystalline composite fibers were synthesized by electrospinning, and pure phase garnettyped Y3Al5O12∶Tb3+(denoted as YAG∶Tb3+ for short) luminescent nanofibers were fabricated by calcinating the obtained composite nanofibers at 900 ℃ for 10 h. The diameter of YAG∶Tb3+ nanofibers was ca. 70 nm, and the length was greater than 100 μm. The water, organic compounds and nitrate salts in the prepared composite nanofibers were decomposed and volatilized totally, and the mass of the sample kept constant when the sintering temperature was above 550 ℃, and the total weight loss percentage was 86.7%. YAG∶Tb3+ luminescent nanofibers emitted bright green light of 543 nm in a wavelength of Tb3+ ion characteristic emission under the excitation of 273 nm ultraviolet ray. The formation mechanism of YAG∶Tb3+ luminescent nanofibers was discussed. This method can be applied to prepare other rare earth garnettyped compound nanofibers.