The study evaluated the effect of preoperative warming in combination with dexmedetomidine on postoperative delirium in patients older than 50 years undergoing hip fracture surgery. A randomized controlled trial enrolled 197 patients who were divided into three groups: heating plus dexmedetomidine (WD), heating alone (W) and a control group (C). The incidence of postoperative delirium was 49.1% in the control group, 26% in the rewarming group, and 14% in the combined intervention group (P < 0.001). The duration of delirium was significantly shorter in the combined intervention group. Intraoperative body temperatures were higher in the warm-up and combination groups versus the control. Postoperative pain scores were lower in the intervention groups and MoCA scores were higher in the combined group, indicating better cognitive function. Inflammatory markers and adverse events were reduced in the combination group. Preoperative warming with dexmedetomidine was associated with a lower incidence and shorter duration of postoperative delirium.