Abstract: The hot compression test was performed on Al-1.04Mg-0.85Si-0.01Cu aluminum alloy by Gleeble-1500 thermal simulation tester, the thermal deformation behavior of the alloy in the temperature range of 300-500 ℃ and strain rate range of 0.001-1.0 s-1was studied, and the microstructure was analyzed by optical microscopy after deformation under different conditions. The results show that the hot deformation behavior of the alloy could be described by a constitutive equation in hyperbolic sine function. When the strain rate was less than 1.0 s-1 , the deformation activation energy of the alloy rose with the increase of temperature and strain rate, however, the deformation activation energy decreased when the strain rate was 1.0 s-1. The calculated value of hot deformation activation energy of the aluminum alloy was 193.029 kJ·mol-1, and it was less than the deformation activation energy of 6061 alloy. The tested alloy has excellent hot workability.