Binary Al-4Mg alloy have been deformed by hot torsion at 300-500℃ and strain rates of 0,006-1.587 s-1 to a true strainof 5.5. The specimens were annealed in vacuum for 1.5 h at 500℃ and then water quenched. The study indicates that the dynamicrecrystallization occurs during hot torsion of Al-4Mg alloy in a certain range of Z parameter (Zener-Hollmon Parameter), i.e. 19.3 ≤lnZ ≤ 24.8. Increasing the strain rate at higher deformation temperature or reducing the strain rate at lower deformation temperatureaccelerates the occurrence of dynamic recrystallization in the alloy.