Photovoltaic systems provide sustainable energy solutions, yet their ecological impacts, particularly on soil carbon accumulation, remain poorly understood in arid ecosystems. This study comprehensively assessed how solar-tracking photovoltaic systems (ST-PVS) influence soil carbon accumulation in a desert steppe by analyzing soil water, extracellular enzyme activities, microbial communities, and vegetation across different micro-zones/ positions (Beneath panel, West edge of panel, East edge of panel, and Between panels). Our results demonstrated that ST-PVS significantly improved soil water distribution, particularly at the Between and East edge positions, where optimized soil water conditions promoted plant biomass production and plant diversity, respectively. These vegetation changes drove shifts in soil microbial communities, notably increasing the abundance of Proteobacteria and Ascomycota. Correspondingly, enhanced activities of (3-1,4-glucosidase, cellobiohydrolase, and (3-1,4-N-acetylglucosaminidase accelerated the transformation of plant-derived organic matter into different soil carbon fractions. Structural equation modeling confirmed that soil water initiated this cascade mainly by promoting plant growth and modifying fungal community structure, with enzyme activity serving as the direct driver of carbon accumulation. However, the Between position achieved the highest carbon accumulation, mainly supported by maximum plant biomass, while East edge mainly supported by superior plant diversity. Unlike fixed photovoltaic systems that often cause soil degradation beneath panels, ST-PVS maintains favorable micro-environmental conditions across all zones, simultaneously supporting energy generation and ecological restoration. These findings may establish ST-PVS as an integrated solution for enhancing soil carbon accumulation and sustainable land management in arid and semiarid regions.