<p>Owing to the low solid solubility and active chemical properties of rare-earth elements in aluminum matrix, the precipitation strengthening effect brought about by rare-earth modification in aluminum alloys has emerged as a focal point among researchers. The objective of this study was to elucidate the effect of cerium (Ce) modification on the high-temperature strength and microstructures of 2024 aluminum alloy (AA2024). The investigation conducted by us primarily focuses on mechanical property testing under ambient/high-temperature conditions, in-depth microstructural analysis, and systematic studies of phase transformations. By introducing 0.46 wt.% of Ce doping into AA2024, the presence of Ce-containing Al₂₄Cu₈Ce₃Mn and Al₁₁Ce₃ phases, along with the finer θ′(Al₂Cu) phases, collectively contribute towards enhancing the high-temperature strength of AA2024. Ce effectively inhibited the precipitation and coarsening process of aging strengthening phases in AA2024, resulting in the formation of denser and finer θ′ phases during high-temperature deformation. The ultimate tensile strength of the 0.46 wt.% Ce-modified AA2024 reaches 202 MPa at 300°C, representing a 23.17% increase compared to the pure AA2024.</p>