The experimental stress–strain data from isothermal hot compression tests, in a wide range of temperatures (350–500 °C) and strain rates (0.005–0.5 s−1), were employed to develop constitutive equations in a commercially pure aluminum (AA1070). The effects of temperature and strain rate on the hot deformation behavior were represented by Zener–Hollomon parameter including Arrhenius term. The results show that the hardening rate and flow stress are evidently affected by both deformation temperature and strain rate. The power law, exponential, and hyperbolic sinusoidal types of Zener–Hollomon equations were used to determine the hot deformation behavior of AA1070. The results suggested that the highest correlation coefficient was achieved for the hyperbolic sine law for the studied material. So the proposed deformation constitutive equations can give an accurate and precise estimate of the flow stress for AA1070, which means it can be used for numerical simulation of hot forming processes and for choosing proper forming parameters in engineering practice accurately.