Abstract: OBJECTIVE To investigate the promoting effect of simvastatin on tibia fracture healing in rats and its related signal pathway. METHODS The right tibia fracture model of 64 male SD rats was established and divided into short-term group, gradual withdrawal group, continuous group and control group according to the different administration of simvastatin. At 4 time points of 1, 2, 3, 4 weeks after operation, 4 rats in each group were randomly selected and killed. X-ray examination, bone tissue HE staining and serum RANKL,OPG level were used to analyze the difference. RESULTS X-ray examination:4 weeks after operation, the healing of the gradual withdrawal group and the fracture line of the continuous medication was good, with only a small amount of residual bone residual. The short-term group was still visible bone fracture and fracture line. HE staining of bone tissue:2 weeks after operation, the prepared bone began to form and hematopoietic cell foci could be seen in the treatment group. At 4 weeks after operation, lamellar bone formation was found in the short-term group, but the direction of bone arrangement was disordered. A large number of bone cells were deposited in the bone matrix in the gradual withdrawal group. The level of serum RANKL in the short-term group was significantly lower than that in the control group after 2 weeks of operation(P<0.05). The trend of serum RANKL gradually decreasing with time in the continuous group was the most obvious. In the third week after operation, the short-term group peaked significantly higher than the other three groups. The level of serum OPG in the treatment group was significantly higher than that in the control group at the 2nd week after operation(P<0.05). and the level of serum OPG in the short-term group was higher than that in other group at the 4th week after operation(P<0.05). CONCLUSION Simvastatin has a certain effect on the healing of the fracture, but the sudden drug withdrawal can have a significant adverse effect on the fracture healing.