Y3Al5O12 (YAG) and Yb∶Y3Al5O12 (Yb∶YAG) single crystals with Yb3+ doping atomic number fraction of 5%, 10%, 15%, 20%, 25%, 50%, and 100% were grown by the Czochralski method. The effects of Yb3+ doping level on the Raman spectra were studied. There were little abrupt change of the vibration modes and little change of the crystal structure with the increase of Yb3+ doping level in Yb∶YAG crystals; but the fullwidth at half maximum of absorption peak centered at 370 cm-1 and 785 cm-1 increased with the increase of Yb3+ doping level. The results show that Yb3+ doping level influences the lattice, symmetry and fluorescence lifetime of Yb∶YAG crystals and this may influence the spectrum and lasing properties of the crystals.