A joint research team from Beihang University systematically uncovered the evolution of precipitate characteristics in Al-Mg-Sc-Ti alloys fabricated via wire-arc additive manufacturing (WAAM) under different aging temperatures, and established a quantitative relationship between precipitate features and mechanical properties. The study found that solution treatment at 500°C for 1 hour fully dissolved coarse brittle eutectic phases, while aging at 320°C for 10 hours resulted in the highest number density and most uniform distribution of Al₃Sc nanoprecipitates. After heat treatment, the ultimate tensile strength along the scanning direction increased from 267 MPa to 367 MPa (a 37% improvement), and elongation after fracture rose from 13% to 17%, achieving simultaneous enhancement of strength and ductility in WAAM-processed Al-Mg-Sc-Ti alloy. This provides data support for optimizing heat treatment processes for additively manufactured aluminum alloys.