Pure ZnO ceramics and GZO (Ga:ZnO) ceramics were prepared by solid phase reaction method. We measured GZO ceramics with different Ga concentration by Raman spectroscopy and X-ray diffraction, and studied the variation of Raman spectra of the samples. The results showed that pure ZnO and GZO ceramics were maintained a hexagonal wurtzite structure. E2(low) and E2 (high) who were the characteristic bands of ZnO were found in 98 cm-1 and 437 cm^-1, respectively. There appeared new bands at the 584 cm-1 and 631 cm^-1 in the Raman spectra of GZO ceramic. And the band at around 1148 cm^-1 corresponding to an overtone of E1(LO) mode has also undergone some changes with the increasing of Ga doping concentration. We assigned the vibration mode of the new band and the change of the original band after doping, which for 631 cm^-1,we believed that this band is attributed to the local vibration mode that the substitution of Ga for Zn with O. (LVMGa-O) .