The objective of this study was to review the clinical features of oral and maxillofacial space infection(OMSI), and to identify the risk factors predisposing to complications.A retrospective study was carried out in the OMSI patients treated in the Peking University School of Stomatology from August 2008 to September 2013, and logistic regression was applied to analyze the risk factors predisposing to complications.A total of 127 cases were enrolled in the study including 75 males (59.1％) and 52 females (40.9％), with an age range of 1-88 years (mean 45.39 years).The most common cause of OMSI was odontogenic infection (57.5％).The most common space involved was the submandibular space, followed by the submental space, the masseteric space and the pterygomandibular space.The most common symptom or sign was swelling (100％), followed by pain (96％) and trismus(89％).All of the patients were treated by empirical antibiotics and surgical incision and drainage, and supportive treatment, and the control of the underlying systemic diseases, and the management of the pathogens at the same time or later, and according to the bacterial culture results whether the change of the antibiotics needed.The positive incidence of the bacterial cultures was 66.4％ (delivery rate was 86.6％), and the predominant bacteria cultured were viridans group streptococci (VGS) (48.2％) and staphylococci (11.8％).The mean time of hospitalization was 7.91 4.69days (range 1-31 days).Sixteen patients developed complications, and the dominant complication was respiratory obstruction, followed by sepsis, septic shock, descending mediastinitis, and pneumonia.In multivariate logistic regression analysis, NEUT％ ranging from 75.0％ to 84.9％ was found to be a risk factor predisposing to complications.The The empirical antibiotics therapy with the second-generation or third-generation cephalosporins, and incision and drainage, and the control of the underlying systemic diseases, and supportive treatment, and the management of the pathogens is a most effective treatment.The MSI patients with NEUT％ ranging from 75.0％ to 84.9％ maybe have a higher risk predisposing to complications, and should be closely monitored.