Abstract: Isothermal compression tests were conducted on electron beam cladding solidified Inconel 718 alloy (EBLS 718 alloy) and electron beam refining Inconel 718 alloy (EBS 718 alloy). The deformation temperatures were 1 010, 1 050, 1 100, 1 140 ℃, and the strain rates were 0.001,0.01,0.1,1 s^-1. The thermal deformation rheological behaviors of the two alloys were compared and studied. Based on the Arrhenius constitutive equation, the constitutive equations of the two alloys were established. The results show that the rheological behavior of the two alloys under different deformation temperatures and strain rates was similar; the flow stress increased with increasing strain rate, and decreased with increasing deformation temperature. Due to the layered interface, the EBLS 718 alloy exibited yield decrease phenomenon at a lower temperature during hot compression deformation, lower deformation activation energy, and more obvious dynamic softening effect. The main deformation mechanism of the two alloys was mainly high temperature climbing mechanism caused by lattice self diffusion.