Abstract: The test of multi-directional forging（MF） and EBSD of 7075 aluminum alloy were carried out. Based on the true stress-strain curves at different temperatures obtained by thermal simulation test, the Arrhenius hyperbolic sinusoidal constitutive equation model was established. The Deform-3D software was used to simulate the temperature field, the equivalent strain and the maximum principal stress of 7075 aluminum alloy during the four passes of MF experiment. The results show that the maximum and the minimum grain size of the forgings is 20.8 and 0.106 μm, respectively. The results are consistent with the results of bimodal grain size obtained by MF experiment and EBSD testing, which shows the accuracy of numerical simulation.