Amidst the dual challenges of coal gangue accumulation and global arable land scarcity, this study pioneers the application of modified coal gangue (MCG) to rehabilitate sandy soils and enhance wheat growth and drought resistance. Through controlled pot experiments, the synergistic improvement mechanisms of the soil-microbeplant system were systematically elucidated. The porous structure and abundant active nutrients (especially silicon and potassium) of MCG significantly enhanced sandy soil quality: aggregate stability and enzyme activity elevated markedly, water holding capacity increased by 17.3%-29.1%, evaporation mitigation capacity significantly rose by 17.8%-20.0% at 40 degrees C, available silicon and potassium levels surged 8.25-31.46 times and 2.67-10.30 times, respectively. Microbial analysis revealed that MCG enriched saprotroph by 21.3%-39.8%, suppressed pathogen and parasite by 47.7%-99.8%, and strengthened the connectivity and anti-interference capability of microbial networks. Meanwhile, bacterial functional profiles exhibited high redundancy and metabolic stability, ensuring robust soil metabolic potential. The application of MCG significantly alleviated drought stress in wheat; under drought stress, the wheat biomass treated with 2.5% MCG increased 5.21 times compared to the control group. The underlying drought resistance mechanism primarily involves enhancing plant nutrient uptake, activating antioxidant enzyme activity (POD, SOD, CAT) and reducing reactive oxygen species (H2O2 decreased by 20.0%-31.8%, O2 center dot- by 26.5%-51.9%), thereby protecting stomatal integrity and photosynthetic function. Economic analysis confirmed that MCG reduced input costs by 26.0% compared to traditional organic fertilizers, alongside carbon sequestration benefit. This research provides an innovative solution for coal gangue resource utilization, sandy soil remediation, and sustainable agricultural development in arid regions.