Novel nanostructures of Y3Al5O12:Dy3+ (denoted as YAG:Dy3+ for short) nanobelts were fabricated by calcination of the relevant electrospun PVP/[Y(NO3)(3) + Dy(NO3)(3) + Al(NO3)(3)] composite nanobelts. YAG:Dy3+ nanobelts are cubic in structure with space group of I(a)3d. The thickness and width of the YAG:Dy3+ nanobelts are respectively 112.45 nm and 3.85 +/- 0.90 mu m under the 95% confidence level. Under the excitation of 352-nm ultraviolet light, the emission bands in the 450-460 nm (at 452 nm) blue region, 470-500 nm (at 484 nm) blue region and 570-600 nm (at 583 nm) yellow region corresponding to I-4(15/2) -> H-6(15/2), F-4(9/2) -> H-6(15/2) and F-4(9/2) -> H-6(13/2) energy levels transitions of Dy3+ ions, respectively. It is found that the optimum doping molar concentration of Dy3+ ions for YAG:Dy3+ nanobelts is 1%. CIE analysis demonstrates that the emitting colors of YAG:Dy3+ nanobelts are located in the blue region and color-tuned luminescence can be obtained by changing doping concentration of Dy3+, which could be applied in the field of optical telecommunication and optoelectronic devices. The possible formation mechanism of YAG:Dy3+ nanobelts is also proposed.