Al-Li alloys present significant challenges for conventional fusion-based additive manufacturing (AM) due to their low evaporation temperature and high reactivity with oxygen. As a solid-state process, friction stir additive manufacturing (FSAM) is expected to eliminate melting and solidification during processing, thereby overcoming these limitations. This study investigates the FSAM of 2195 Al-Li alloy through temperature measurements and numerical simulations. The research focuses on the temperature at the center of the deposited region and the phase evolution before and after FSAM. The results indicate that during FSAM, the temperature at the center of the deposited zone ranges from 458 to 497 °C. In terms of phase constitution, the T3-tempered alloy primarily consists of an α-Al matrix and the δ’ (Al₃Li) phase. The T8-tempered alloy contains α-Al, θ’ (Al₂Cu), and T₁ (Al₂CuLi) phases. In the nugget zone (NZ), the peak temperature exceeds 450 °C. As a result, the T₁ and θ’ phases dissolve, leaving only a small amount of δ’/β’ precipitates. This study presents a preliminary investigation based on a single-layer FSAM process. These findings provide a foundation for optimizing FSAM process parameters for Al-Li alloys.