Abstract: High-strength fluidized solidified soil can be used as a new type of pile foundation material for stiff composite piles， which can significantly improve the bearing capacity of pile foundations and effectively solve anti-floating problems. This paper used slag powder， steel slag powder， and desulfurization gypsum as the main raw materials to prepare curing agents and cement， which were respectively mixed with construction waste redundant soil to prepare high-strength fluidized solidified soil and study its mechanical properties. The results showed that the use of curing agents for preparing high-strength fluidized solidified soil exhibited advantages over cement soil， such as higher strength， lower cost， and lower carbon emissions. The unconfined compressive strength of cured soil samples increased with the increase of curing agent dosage and curing age. With the increase of curing agent dosage， the peak stress and elastic modulus of the stress-strain curve of the cured soil gradually increased， while the peak strain and ultimate strain gradually decreased， indicating that the material exhibited more brittle characteristics. and the internal friction angle of the cured soil decreased， but the cohesion increased significantly， resulting in a significant improvement in shear strength. With the increase of curing agent dosage and confining pressure， the triaxial compressive strength increased.