Objective To study the effect of once-weekly injection of recombinant human parathyroid hormone rhPTH(1-34) on the healing of bone fracture in rats.Methods Fifty male 3-month old SD rats were used in this study to produce unilateral tibial fracture and received internal fixation with a Kirschner needle. Based on the dose and frequency of rhPTH (1-34) injection, the rats were randomly divided into five groups (n=10 each) as follows: subcutaneous injections of saline, and rhPTH in a dose of 10, 20, 10, and 20 μg/kg/d.After 4 weeks of treatment, the rats were euthanatized and the fractured tibia were assessed by X-ray, dual energy X-ray absorptiometry (DXA),micro-computed tomography (microCT) and three-point bending test.Results The fracture healing in the 20 μg/kg/w group was better than the saline group.The fracture healing in the 20 μg/kg/w group was as well as the 10 μg/kg/dgroup. The BMD of 20 μg/kg/w group was 26.2% higher than the saline group. The mineralized callus volume in the 20 μg/kg/w group was 51.4% higher than the saline group. The total callus volume in the 20 μg/kg/w group was 21.6% higher than the saline group. The ultimate load of the 20 μg/kg/w group was 29.3% higher than the saline group. There was no significant difference between the 20 μg/kg/w group and 10 μg/kg/d group in BMD, bone micro-architecture,and biomechanical strength (P>0.05). Conclusions Once weekly injection of rhPTH (1-34)can promote the bone fracture healing.