Objective Gunshot wound spreads to the surrounding tissues and organs, it is difficult to debride and easy to infect. The conventional treatment is thorough, extensive debridement, fully open drainage, which often causes normal tissue damage and compl ications. To evaluate the effectiveness of vacuum seal ing drainage (VSD) treating thepenetrating wound in porcine extremity by MRI and pathological methods so as to provide theoretical basis for future cl inical use. Methods Eight healthy adult pigs, weighing (45 ± 5) kg, were selected. Eight pairs of hind l imb penetrating wounds (16 wounds) were made by using Chinese-made 95-type rifle at 25 meters distance, which were randomly divided into experimental group (left side, n=8) and the control group (right side, n=8). After debriding and disinfecting the penetrating wounds at 6 hours after injury, wounds were treated with VSD in experimental group. The ball istics exports of the wounds were covered with single-layer gauze and imports were directly sutured and covered with sterile gauze in control group. The trajectory and the general condition of the adjacent skin were observed. MRI and histological observation were taken at 5, 24, 48, and 72 hours after injury, bacterial counting analysis was done at 0, 12, 24, 48, and 72 hours after injury. Results The aperture of the trajectory exit and entry were (5.00 ± 2.50) cm and (0.30 ± 0.15) cm immediately after injury. The wound surface was clean, rosy without leakage and swell ing after 72 hours in experimental group; wound and adjacent tissue were swell ing obviously, pus, muscle necrosis and exfol iative tissue was observed, and deep defect cavity at the trajectory exit could be seen in control group. MRI showed that pairs of l inear low signal in T1WI and T2WI was seen in trajector of experimental group at 5 hours after injury, and signal in T1WI gradually increased at disrupted area and tissue deformation area at 24, 48, and 72 hours; in control group, low signal in T1WI was observed at 5 hours after injury, and signal in T2WI gradually increased and a clear boundari between edema and surrounding tissue, and the increase of signal in T1WI was not obvious at 24, 48, and 72 hours. The histological observation showed that wound was dominated by effusion at 5 hours after injury, granulation tissue gradually increased, muscle tissue dissolved and inflammatory cell infiltration was not obvious at 24, 48, and 72 hours in experimental group; in control group, the gradual dissolution of muscle fibers and inflammatory cell infiltration were observed at 5, 24, and 48 hours, muscle tissue became swell ing, dissolving and degeneration and a large number of inflammatory cell infiltration gathered into the bacteria group at 72 hours. There was no significant difference in the number of bacteria per gram of tissue (P gt; 0.05) between experimental group and control group at 0 hour after injury; the numbers of bacteria in control group were significantly higher than those in experimental group at 12, 24, 48, and 72 hours (P lt; 0.05). Conclusion MRI combined with pathology show diagnostic meaning in treatment of gunshot wound with VSD. MRI can accurately reflect the scope of l imb gunshot wound 72 hours after injury. VSD may be an approach to delay infective time, shorten wound heal ing time, and promote the growth of healthy granulation tissue.