Activated coke waste (ACW), a byproduct of industrial desulfurization and denitrification, consists of fine particles ( Na+ > Cl-. Isothermal adsorption analysis revealed that Na+ and Cl- adsorption aligned with the Langmuir model, whereas SO42- adsorption adhered to the Freundlich model. Application of SACW (>= 10 g kg(-1)) effectively improved saline-alkali soil properties by lowering pH and salinity, enhancing soil aggregate stability, and promoting nutrient utilization efficiency. Notably, SACW-treated soils supported maize plants with significantly increased height and biomass (13.94% and 159.28% higher, respectively; P <= 0.05) compared to untreated controls. These benefits stemmed from improved nutrient availability and reduced salt stress-induced plasma membrane damage. These findings validate SACW as a sustainable, functional amendment for reclaiming saline-alkali ecosystems and boosting crop productivity.