Background and Aims <p>Biostimulants, including artificial humic acid (A-HA) and microbial inoculants, are gaining attention for enhancing soil fertility and crop growth. This study explores their combined effects on rhizosphere soil organic carbon (SOC) fractions and microbial activity.</p> Methods <p>In this investigation a pot experiment of maize was carried out with six treatments, including the synergistic or independent action of artificial humic acid and microbial agents, and a control. Then soil at various growth stages were collected to determine organic carbon, enzyme activity, microorganism community structure, and the growth of the maize, which has been calculated and analysed by high throughput sequencing, principal component analysis and Shannon index to evaluate the effects of different treatments.</p> Results <p>A-HA at 200&#xa0;mg/kg enhances the availability of nutrients, enzyme activity, root development and favors superior growth, better yielding capacity and increasing stability of soil carbon with microbial agents. It increases soil humification, decreases the activity of enzymes for carbon turnover at 400&#xa0;mg/kg, decreases gene abundance for metabolism of nutrients, increases gene abundance for carbon fixing microbes and gene abundance of stable pathway of carbon so as to increase the active organic carbon to stable organic carbon and elevate the content of overall soil organic matter.</p> Conclusion <p>The combined application of A-HA and microbial inoculants significantly enhanced SOC fractions and soil nutrient conditions, while stabilizing microbial community abundance in the rhizosphere. This study provides theoretical guidance for improving crop yield through practical application of these soil amendments.</p>