Abstract： Objective To analyze the causes associated with the failure of dental implant restoration. Methods The patients who received dental implant restoration from January 2001 to December 2008 in Center of Dental Implant, School of Stomatology, Shandong University were reviewed and analyzed.The cases with implant loosening, broken or removed were considered failure. Results There were a total of 38 failure implants in 32 patients found in this group of patients. Of those, 33 implants loosened (17 cases before restoration and 16 cases after restoration), two were broken, two retention screws broken and one implant perforated on buccal side. The causes of failure included doctor-related factors in 19 cases, patientrelated factors in 9 cases, implant-related factors in two cases and two uncertainties. Conclusions Doctorrelated factor is the main cause of dental implant failure, followed by patient-related factor and implantrelated factor.