Abstract: Ginseng (Panax ginseng), a traditional and valuable Chinese medicinal herb, requires highly specific soil conditions for optimal cultivation. The growth and development of ginseng are often severely restricted by the high bulk density and low organic matter content typical of conventional farmland soils.In this study, magnesium hydride (MgH₂) was innovatively incorporated into a microbial organic fertilizer. Using three-year-old ginseng plants as experimental materials, a large-scale field experiment was conducted to systematically investigate the effects of different application rates (0, 1.25, 2.5, and 5 kg·m⁻², designated as HD-CK, HD-1, HD-2, and HD-3, respectively) on ginseng agronomic traits, soil physicochemical properties, and enzyme activities.Results showed that moderate application (HD-2 treatment, 2.5 kg·m⁻²) significantly promoted ginseng growth. The seedling survival rate reached 89.11%, which was 12.87% higher than that of the control. At the wilting stage, plant height, leaf area, and chlorophyll content increased by 40.95%, 74.14%, and 15.13%, respectively.In terms of soil fertility, the HD-3 treatment yielded the greatest improvements, with organic matter, total nitrogen, and total phosphorus contents increasing by 27.53%, 38.27%, and 43.32%, respectively, compared with the control. Soil enzyme activities were also significantly enhanced, with sucrase, urease, amylase, and cellulase activities during the green fruit stage increasing by 322.73%, 42.36%, 63.87%, and 82.50%, respectively, under HD-3 treatment.Overall, the HD-2 treatment (2.5 kg·m⁻²) was identified as the most effective for promoting ginseng growth and improving soil quality. The MgH₂–microbial organic fertilizer enhanced soil health and optimized microbial community structure through the synergistic effects of hydrogen, magnesium, and microorganisms, comprehensively improving soil physicochemical properties and enzyme activities, thereby promoting ginseng growth and development.Furthermore, the application of MgH₂–microbial organic fertilizer increased the relative abundance of beneficial soil microorganisms, enriched soil metabolic pathways, and reduced the abundance of the pathogenic fungus Fusarium spp., effectively promoting ginseng growth while lowering the risk of root rot disease.This study provides an innovative technological pathway and theoretical basis for applying hydrogen in agricultural soil improvement, offering significant practical value for the green, efficient, and sustainable cultivation of valuable Chinese medicinal plants. Future research will focus on the dynamics of hydrogen release and its influence on rhizosphere microbial community structure to support the precise application and industrial development of this fertilizer.