Background <p>Herbaceous plants serve as one of the primary fuel types in terrestrial ecosystems and strongly influence fire behavior by determining their flammability. The enhancement of plant flammability is an adaptation to fire-prone ecosystems.</p> Methods <p>We analyzed the interaction among traits, physicochemical properties, flammability characteristics of <i>Miscanthus floridulus</i> and soil physicochemical properties in the subtropical high-frequency fire areas and no-fire areas.</p> Results <p>Our results show that <i>M. floridulus</i> exhibits high flammability characteristics: high biomass, high height, large crown diameter, and basal stem diameter. <i>Miscanthus floridulu</i>s has lower equilibrium moisture content and ash, higher cellulose and lignin content, and shows flammable physicochemical properties, resulting in easier ignition and faster spread. Soil available Nitrogen of 82.6&#xa0;mg/kg, available phosphorus of 1.67&#xa0;mg/kg, and high biomass (2105.6&#xa0;g·m⁻²) showed a significant positive correlation in high frequency fires area.</p> Conclusions <p>Our findings indicate that fire acts as a key driver of vegetation-soil feedback mechanisms by enhancing the flammability of <i>M. floridulus</i> through increased biomass, cellulose, and lignin content, alongside reductions in moisture and ash content. These trait changes correlated closely with altered soil conditions, including higher nutrient availability and lower moisture. These insights can inform fuel management and fire prevention strategies in subtropical fire-prone ecosystems.</p>