Objective To study the effect of the human umbilical cord blood on the content of trace elements in whole blood during fracture healing in rabbits and to explore the mechanism of promoting fracture healing. Methods The right tibial fracture model was made in 63 white New Zealand rabbits (aged, 4-5 months; weighing, 2.0-2.5 kg). The fracture site was treated with 3 mL human umbilical cord blood (group A, n=21) and 3 mL normal saline (group B, n=21) at 3 and 8 days after operation, and was not treated as a control (group C, n=21). At 1, 2, 3, 4, 5, and 6 weeks after operation, the X-ray and histological observations were done; the contents of zinc, copper, magnesium, ferrum, calcium, and phosphorus were detected. Results X-ray observation showed that the fracture healing speed of group A was significantly faster than that of groups B and C; the fracture healing X-ray score of group A was significantly higher than that of groups B and C at 2-6 weeks (P lt; 0.05). The histological observation indicated that new trabeculae and osteoid of group A were significantly more than those of groups B and C; at 2-5 weeks, the histological score of group A was significantly higher than that of groups B and C (P lt; 0.05); at 6 weeks, the score of group A was significantly higher than that of group B (P lt; 0.05), but no significant difference was found between groups A and C (P gt; 0.05). Changes trend of the trace elements in 3 groups after operation was basically consistent. The content of copper first decreased and then gradually increased; the contents of ferrum, zinc, and magnesium at different time points decreased, but were basically stable; the content of calcium first increased and then decreased; the content of phosphorus first decreased and then increased. The contents of copper, zinc, magnesium, ferrum, calcium, and phosphorus in group A were significantly higher than those in groups B and C at different time points (P lt; 0.05), but there was no significant difference between groups B and C (P gt; 0.05). Conclusion Injection of the human umbilical cord blood at the fracture end of rabbits can significantly slow down the loss of trace elements in whole blood, ensure the contents of necessary trace elements during fracture healing, which may be one of the mechanisms of the umbilical cord blood promoting fracture healing.