Abstract: OBJECTIVE To investigate the clinical characteristics and treatment outcomes of diabetes mellitus patients with oral and maxillofacial space infection, so as to provide clinical basis for the treatment of diabetic patients with oral and maxillofacial space infection. METHODS A total of 150 cases of patients with oral and maxillofacial space infections admitted from Feb. 2015 to May 2016 were retrospectively analyzed. According to the presence or absence of diabetes mellitus, they were divided into diabetes group with 68 cases and non-diabetic group with 82 cases, and the clinical characteristics and treatment outcomes of the two groups were compared. RESULTS The main cause of the two groups of patients was odontogenic infection, the location of infection was mainly in the lower part of the face, and the age and the number of the space involved of the two groups had significant differences(P<0.05). The common bacteria were Klebsiella pneumoniae in diabetes group and Streptococcus non-diabetic group. The blood glucose level of diabetic group was higher than that of non-diabetic group, and the incision number of incision and drainage, the hospitalization days and the incidence of complications of the two groups had significant differences (P<0.05). CONCLUSION The clinical characteristics of diabetes mellitus and non-diabetic patients with oral and maxillofacial space infection are quite different. Diabetes mellitus affects the treatment of multiple gap infection in oral and maxillofacial region.