Objective To study clinical effects of the pulsed electromagnetic fields(PEMFs) combined with autologous red marrow implantation in the treatment of traumatic bone defect.Methods Patients with fresh fractures of the limbs were divided into three groups randomly. The allograft cancellous bone was implanted into the bone defect region before routine fixation in the control group. For 2 Hz and 15 Hz study groups, internal fixation was carried out after the blended autologous red marrow and allograft cancellous bone were implanted, then treated with PEMFs of 2 Hz, 15 Hz. X-ray examination was performed at 4,12,24,40 weeks after fixation in all patients and the effects were evaluated.Results All the 30 patients were followed up after treatment, the cure rates in control group, 2 Hz, 15 Hz study groups were 80%, 100%, 90%, respectively. The formation of bony callus in the study groups were significantly higher than that in the control group at the same time point (P<0. 05), and the formation of bony callus in PEMFs group of 2 Hz was higher than those in the group of 15 Hz (P<0. 05). The functional recovery of upper and lower limbs had no significant difference between the three groups (P<0.05).Conclusions PEMFs combined with the composite of allograft cancellous bone and autologous red marrow can promote the growth of bony callus significantly, and is effective to repair bone defects.