Abstract: A novel method for in-situ preparation of Al-Cu-Li alloy by bypass arc directed energy deposition is proposed. This process uses ER2319 as the main wire material and introduces 2A97 strip-shaped intermediate alloy through the bypass to prepare Al-Cu-Li alloy. By analyzing the macroscopic morphology, metallographic structure, and microhardness of components deposited by different processes, the CMT-P process was selected for bypass arc additive manufacturing forming experiments. Single-pass deposition experiments were conducted by varying the welding current, deposition speed, and bypass feeding speed. The surface and cross-sectional morphology of the single-pass weld were observed, and the optimal parameters during the forming process were determined. Based on this, the feeding speed of the bypass intermediate alloy was set. This new bypass feeding technology provides a new option for the in-situ synthesis of high-strength aluminum alloy additive manufacturing