Peripheral coarse grain (PCG) structure is a typical defect occurring to extruded medium-and high-strength aluminum alloys. It is caused by localized recrystallization and detected during product quality control at extrusion plants or during failure analysis at customer's sites. It may seriously degrade extruded products in mechanical properties. The occurrence of localized recrystallization in the AAVxxx series aluminum alloys is associated with a combination of factors including alloy chemistry, microstructure prior to extrusion, extrusion condition, die geometry and die surface condition in a complex manner. In this paper, the effects of alloying elements and homogenization practice on recrystallization and grain growth after extrusion are discussed. Methods that can be used to prevent or at least minimize this defect are put forward.