Objective To explore the effect of vacuum sealing drainage technique in flap repair of lower leg injury wound and its influence on postoperative healing and infection. Methods A total of 50 patients who underwent flap repair for lower leg injury wound at our hospital from June 2021 to December 2024 were selected as the research subjects, and they were divided into the control group (n =25) and the observation group (n =25) by the random number table method. The control group received conventional treatment, and the observation group received vacuum sealing drainage technique on the basis of the control group. The flap survival rate, wound healing time, infection rate, satisfaction, pain and functional recovery were compared between the two groups. Results The complete flap survival rate of the observation group was higher than that of the control group (P <0.05). The wound healing time in the observation group was (13.42±2.15)d, which was shorter than (18.08±2.62)d in the control group (P <0.05). The infection rate in the observation group was 8.00%, which was lower than 24.00% in the control group (P <0.05). The satisfaction score of the observation group was higher than that of the control group (P <0.05). The VAS scores in the observation group at 24 hours, 48 hours, and 1 week after surgery were lower than those in the control group (P <0.05). The motor function recovery score of the observation group was higher than that of the control group (P <0.05). Conclusion The application of vacuum sealing drainage technique in flap repair of lower leg injury wound can promote flap survival, shorten the healing cycle, reduce the incidence of infection, promote functional recovery, and improve treatment satisfaction, with high clinical applicat ion value.