Objective:To explore whether the lack of endogenous PTH causes angiogenesis weakness by reducing the expression of VEGF during fracture healing and delays fracture healing. Methods:We constructed PTH knockouted mice fracture model,and observed fracture healing from X-ray film and detected bone anabolism and angiogenesis using immunohistochemistry. Results:VEGF expression was decreased in PTHKO mice. Immunohistochemical analysis showed that positive PEGAM was reduced. OCN activity was decreased and fracture healing was delayd. Conclusion:Lack of endogenous PTH may release VEGF by reducing mesenchymal stem cells or osteoblasts,reduce vascular fracture,inhibit osteoblastic activity,surpress endochondral ossification and lead to fracture healing delay eventually.