Cerium-doped gadolinium gallium aluminum-based garnet ceramics Gd 3 (Al 1-x Ga x ) 5 O 12 ∶Ce (abbreviated as GAGG∶ Ce) have the properties of high light output, short afterglow, fast attenuation, and high X-ray blocking ability, which make them a research hot spot in recent years with a wide range of applications in the fields of medical imaging, high-energy ray detection, and high-power LED lighting. The preparation of high-performance GAGG transparent ceramics relies on the technology of preparing ultrafine, highly dispersed, non-agglomerated, and high sintering activity nanopowders. This paper reviews the research progress made by domestic and foreign researchers in recent years on the synthesis of GAGG nanopowders by the chemical co-precipitation method, analyzes the related mechanism of powder preparation by the co-precipitation method and the main factors affecting the performance of the powder, and looks forward to the research prospects and development direction of the preparation of high-performance gadolinium gallium aluminum-based garnet powders by the chemical co-precipitation method.