There are many problems such as polycrystal twisted growth and component segregation during the preparation of the new scintillation crystal Gd₃(Al,Ga)₅O₁₂:Ce (abbreviated as GAGG:Ce) by the Czochralski method. In order to solve these problems to obtain large-size and high-quality GAGG:Ce crystals, with a combination of melt characteristics, formation mechanism of twisted growth, component segregation, spectral characteristics and scintillation performance of GAGG:Ce crystals were studied. A complete GAGG:Ce crystal with size of ϕ50 mm× 120 mm was successfully grown by adjusting the temperature field and inhibiting the volatilization of the components. The results show that light output of the GAGG:Ce crystal sample (10 mm×10 mm×2 mm) is 58000 ph./MeV, while energy resolution is 6.4%@662 keV with transmittance at 550 nm of 82%, decay time of 126 ns (83%), and the slow component is 469 ns (17%). The peak position of emission wavelength of the crystal is about 550 nm, which matches well with the silicon photomultiplier. Meanwhile, the emission weighted longitudinal transmittance is as high as 79.8%. GAGG:Ce crystal has an excellent combination of high light output and energy resolution, and all of these properties show that GAGG:Ce crystal is a promising scintillator for neutron and gamma detection applications.