Objective To investigate the clinical characteristics, etiological factors and pathogenic bacterium of orbital cellulitis. Methods A retrospective clinical study was done on 63 orbital cellulitis patients receiving treatments in Xijing Hospital between 1960 to 2008, and their gender, age, pathogenic approach, pathogens and complications were analyzed. Results Of the 63 patients, 76.2% were males and 23.8% were females. The highest incidence occurred in the 0-10 year old group (34.9%). There were 96.8% of the patients suffered unilateral eye injures, 50.8% of the patients expressed obvious exophthalmos. The pathogenic approaches mainly involved the surrounding tissue infection (47.6%), others included blood stream infections (19.0%), ocular trauma (15.9%) and postoperative infection in the eye (3.2%). Thirty patients had bacterial cultures but only 18 cases (60.0%) showed positive results. There were 4 main pathogens. Staphylococcus was the main pathogen (77.8%), especially staphylococcus aureus (44.4%). In addition, there were pseudomonas (11.1%), A-hemolytic streptococcus (5.6%) and intermediate freund citrobacter (5.6%). Complications included sepsis (12.7%), exposure keratitis (4.8%), panophthalmitis (4.8%), purulent meningitis (4.8%) and cavernous sinus thrombophlebitis (3.2%), etc. Conclusion Orbital cellulitis mostly occurrs in child patients under 10 years of age. Exophthalmos is the primary feature. The main pathogenic approach involve surrounding tissue infection. The positive rate of bacterial cultures is relatively low,in which staphylococcus aureus is the chief pathogen, followed by A-hemolytic streptococcus,pseudomonas, etc. Orbital cellulitis may be accompanied with severe complications and a low rate of positive bacterial culture, therefore a broad-spectrum antibiotic therapy is needed during the early stage, and incision and drainage should be performed in a timely manner for abscess formation.