Abstract: The effects of homogenization treatment at different temperatures and holding time on the microstructure of cast 6063 aluminum alloy were studied by means of optical microscope, SEM and EDS. The results show that the grain size of cast 6063 aluminum alloy is uneven, there are a lot of non-equilibrium phases between dendrites, and the main non-equilibrium phases are granular Mg2Si phase and long rod-shaped Al FeSi impurity phase. With the increase of homogenization temperature and holding time, the non-equilibrium phase on the grain boundary of 6063 aluminum alloy gradually dissolves and the segregation gradually disappears. The segregation of cast 6063 aluminum alloy at 550℃×8 h homogenization treatment is basically eliminated and the grain is uniform, which is an ideal homogenization process for 6063 aluminum alloy.