Experiments were performed to observe the changes of multiple system organ failure (MSOF) and gut barrier function caused by shock and reperfusion after gunshot wounds. Eighteen dogs were divided randomly into two groups. In the experimental group, the dogs were subjected to 60 minutes of shock (40mm Hg), followed by reinfusion of shed blood after hindlimb gunshot wounds. In the control group, the dogs experienced pure gunshot wounds without shock and reperfusion. The results showed that dogs in the experimental group developed multiple system organ injuries or failures compared with the control group. The levels of malondialdehyde (MDA) values in plasma were significantly elevated in the experimental group when compared with preinjury and the control group. Gut flora disorder, bacillus intestinalis overgrowth, and bacterial translocation occurred in the experimental group. The pathological results support the gut barrier function injury. The results indicated that pure gunshot wounds do not easily injure gut barrier function and produce MSOF. Gunshot wounds with shock and reperfusion are capable of causing gut flora disorder, bacillus intestinalis overgrowth, and lead to bacterial translocation, furthermore causing MSOF. Although fluid resuscitation is a potential treatment modality, pathogenically, it can lead to MSOF.