Abstract: A parameter K_max indicating the nature of the materials has been suggested by present work with which the Al-alloys can be classified into two categories:in alloys with K_max<0.1 only continuous dynamic recrystallization can occur and it cannot proceed completely; in alloys with K_max>0.1 occurs only dynamic recrystallization. The characteristics of the dynamic recrystallization of Al-alloys has been discussed.