Background and aims <p>Litter decomposition is a critical process in grassland biogeochemical cycles. However, the synergistic mechanisms by which climate warming regulates it remain poorly understood, particularly regarding the role of trace elements.</p> Methods <p>We simulated climate warming in the Qilian Mountains using open-top chambers (OTCs), with a warming magnitude of 0.42℃ for <i>Agropyron cristatum</i> (<i>A. cristatum</i>) and 0.74℃ for <i>Achnatherum splendens</i> (<i>A. splendens</i>), two dominant species in the Qilian Mountains grassland. Integrative analyses of litter quality, soil enzyme activities, microbial diversity, and trace element dynamics were performed to clarify the regulatory mechanisms of warming on litter decomposition.</p> Results <p>Our findings revealed a species-specific response. Warming significantly suppressed the decomposition rate of <i>A. splendens</i> litter by 11.9%, while showing no effect on <i>A. cristatum</i>. The inhibition of <i>A. splendens</i> decomposition was linked to an elevated litter N:P ratio and reduced fungal diversity under warming. Importantly, warming decreased the dynamics of trace elements in the <i>A. splendens</i> litter-soil system. Structural equation modeling revealed that warming directly regulated litter quality and indirectly modified the microbe-enzyme-trace element interaction network, thereby controlling litter decomposition rates.</p> Conclusions <p>This study reveals that subalpine grassland litter decomposition exhibits distinct, species-specific responses to experimental warming. It highlights the pivotal role of trace elements in mediating microbial and enzymatic processes in the response of litter decomposition to warming. These findings are vital for predicting the impact of climate change on nutrient cycling in grassland ecosystems.</p>