The potassium tantalate niobate KTa_(0.63)Nb_(0.37)O_3 single crystal with large size and good quality was synthesized by Czochralski method.The crystal composition and structure were determined by electric probe microanalysis(EPMA) and X-ray diffraction(XRD) technique,respectively.The sequence of phase transitions of the as-grown crystal was investigated by Raman scattering technique.What features in the phonon spectrum corresponding to each phase transition,namely cubic to tetragonal(C-T),tetragonal to orthorhombic(T-R) and orthorhombic to rhombohedral(O-R),is discussed.Following the features the C-T phase transition point measured is in the vicinity of –40 ℃,and the difference from theoretical value was discussed;T-O phase transition point is at around –130 ℃,while the O-R phase transition point was not obtained due to the band overlapping and experiment limit. The potassium tantalate niobate KTa_ (0.63) Nb_ (0.37) O_3 single crystal with large size and good quality was synthesized by Czochralski method.The crystal composition and structure were determined by electric probe microanalysis (EPMA) and X-ray diffraction , respectively. The sequence of phase transitions of the as-grown crystal was investigated by Raman scattering technique. What features in the phonon spectrum corresponding to each phase transition, namely cubic to tetragonal (CT), tetragonal to orthorhombic (TR) and orthorhombic to the phase transition point is at around -130 ° C. while the OR phase is measured transition point was not obtained due to the band overlapping and experiment limit.