<p>Necking evolution of Ti6Al4V titanium alloy under high-temperature tension at low strain rates is a typical non-uniform deformation with significant strain-rate gradients. Accurately predicting this process contributes to revealing materials’ flow behavior during non-uniform and large plastic deformation. In this work, tensile tests conducted at 700 °C and microstructure characterization indicate that the flow behavior of Ti6Al4V exhibits pronounced strain-rate sensitivity and dynamic recrystallization-induced strain softening. Employing a hybrid experimental-numerical strategy, a physically based model is validated as an effective approach for extrapolating post-necking flow stress curves. Subsequently, two phenomenological models are calibrated using these flow stress curves. By deriving the stress updating algorithms in an implicit finite element method, three visco-plastic models are utilized to simulate tension processes with necking evolution. The results suggest that the physically based model predicts tensile necking processes more accurately compared to phenomenological models, despite using similar flow stress curves. The necking evolution simulated by phenomenological models is notably retarded due to the lack of strain-rate history effects. In contrast, the physically based model, which records the strain-rate history, predicts lower flow stress in the necking center but higher flow stress in regions farther from the center, thereby promoting necking localization. Besides, large time increments in simulations fail to capture strain-rate gradients in necking regions, and a recommended time increment is provided to ensure stable simulations of necking evolution.</p>