Additively manufactured precipitation-strengthened high-entropy alloys exhibit excellent synergy between strength and ductility, demonstrating promising prospects for engineering applications. The rapid solidification characteristics inherent to additive manufacturing introduce unique heterogeneous microstructural features that significantly alter the precipitation behavior and ultimately affect the mechanical properties of these alloys. This review systematically summarizes four typical microstructural characteristics found in additively manufactured precipitation-strengthened high-entropy alloys: heterogeneous grain morphology, solidification segregation, in-situ formed secondary phases, and dislocation networks. Special emphasis is placed on the mechanisms by which these characteristics influence precipitation behavior, including nucleation, growth, and coarsening, during subsequent heat treatment. The tensile properties, strengthening mechanisms, and deformation behavior of these alloys are comprehensively discussed. Finally, current research progress is summarized, and future research directions are proposed.