In this experimental study, maxillofacial regions of dogs were wounded by steel spheres, which weight 1.03 g at a mean primary velocity of 1500 m/s. Aerobe and anaerobe bacteria in the muscles of different interval from wound track edge were cultured at different time after wound. The results showed that there was bacteria infection in the soft tissues between 0 and 0.5 cm from wound track edge in 6 hours after wound. The quantity of bacteria obviously increased following time prolonging, on the contrary, it was much lower than threshold value of bacteria infection within 24 hours. The experimental results suggested that there was obvious bacteria infection in the soft tissues within 0.5 cm distance from wound track edge in maxillofacial firearm wound region. During the debridement removing soft tissues within 0.5 cm distance from wound track edge, the infection of wound region could be controlled. Using effective antibiotics is an important measure of controlling infection of wound after debridement.