Abstract: Objective To investigate the characteristics of posterior tooth fracture and the risk factors preliminarily. Methods Analysis relevant indicators of cases that were diagnosed as posterior tooth fracture clinically and with X-ray from Department of Endodontic of Stomatological Hospital of Jiangsu Province during Sep. 2009 to Sep. 2011. Results 252 tooth（premolars 57 and molars 195）of 252 cases（males 130 and females 122）were involved. The numbers of people of 18～44、45～59 and ＞60 age group were close to each other(82，90，80). The fracture of posterior teeth most occurred on the maxillary first molar (88/252), and least on the mandibular first premolar (2/252). The numbers of crown fracture, root fracture and crown-root fracture were 89, 19 and 144 respectively. 53.97% cases clearly mentioned a history of biting hard objects. The number of the teeth with vital pulp was more than the teeth after root canal treatment (RCT) (P<0.05). Conclusion Molars and teeth with vital pulp took up high proportions of fracture, and fracture often involved crowns and with a history of biting hard objects. No significant relationship between gender, age and tooth fracture was found.