Abstract: Amorphous alloy is a relatively new type of glassy material with a short-range ordered and long-range disordered structure, which has unique physical and mechanical properties. A large number of studies have demonstrated that there exists an intrinsic correlation between the mechanical and physical properties of amorphous alloys and their inherent microstructural heterogeneity. In the current research, the (La_0.6Ce_0.4)₆₅Al₁₀Co₂₅ amorphous alloy is taken as the model alloy. On the basis of the uniaxial tensile tests and stress relaxation experiments, the contributions of physical aging and rejuvenation effects to the deformation behavior of amorphous alloys in the deformation process are effectively separated within the framework of the free volume model. Furthermore, the stress relaxation behavior of the amorphous alloy is quantitatively described using a fractional Maxwell model. The results show that with increasing tensile strain, the amorphous alloys exhibit an elastic phase, a stress-overshoot phase, and a steady-state flow phase, respectively. In the elastic phase, where the strain is small, the rejuvenation due to deformation cannot counteract the effects of physical aging on the amorphous alloy. While the amorphous alloy is in the inelastic deformation stage, due to the larger strain, the rejuvenation caused by deformation cancels out the influence of physical aging; the steady-state rheological stress of amorphous alloys is determined by the strain rate and is not affected by physical aging, and the steady-state rheological stress in the tensile curves of amorphous alloys is the same for different annealing times under the same strain rate. The higher the strain rate, the larger the steady-state rheological stress in the tensile stress-strain curve, the faster the defect concentration increases, and the more obvious the stress overshoot phenomenon.