Soil acidification is one of the major processes driving global soil degradation, significantly undermining the stability of agroecosystems and the functioning of nutrient cycling. Driven by long-term application of ammonium-based fertilizers, acid deposition, and intensive leaching, soil acidification accelerates the transformation of aluminum from inert mineral-bound forms into highly reactive ionic species, leading to the accumulation of soluble, strongly acidic components dominated by Al3+. This process exerts cascading effects on soil physicochemical properties, microbial community structure, and plant root functioning. This review systematically synthesizes the chemical mechanisms by which acidification accelerates aluminum activation, summarizing the processes of aluminum release, complexation, and re-stabilization at the soil-organic matter-mineral interface, as well as their key roles in nutrient retention, structural stability, and biological functional degradation. Furthermore, it analyzes the ecological effects of aluminum activation on nutrient cycling, microbial ecology, and plant aluminum tolerance responses. Finally, based on this synthesis, it is comprehensively evaluated multi-pathway regulatory strategies, including soil amendments, plant-microbe interactions, and management practices. Also, their potential synergistic roles and future directions in mitigating aluminum activation are highlighted. From both chemical and ecological perspectives, this review provides a theoretical basis for advancing the understanding of aluminum activation mechanisms and associated ecological effects in acidified soils, and offers scientific support for the ecological restoration and sustainable utilization of acidic soils.