BACKGROUND: Fracture healing is an extremely complex process in biological repair and reconstruction. Local mechanical environment of the fracture site plays a regulatory role in the process of fracture healing. OBJECTIVE: To design a bone stress stimulator and to carry out the dynamics modeling and parameter identification. METHODS: Based on the mechanism of vibration in promoting bone healing, a bone stress stimulator was designed. A two-degree-of-freedom damped spring system forced vibration model was simplified. Five healthy male volunteers (about 25 years old) were recruited to identify the main parameters of the vibration in promoting bone healing system (the identification of the total stiffness of the rubber spring K1, the plantar muscle stiffness K2, the plantar muscle damping r1, and the kirschner wire bending stiffness K'). The simulated callus amplitude was obtained and the experiments of vibration to promote bone healing were performed. RESULTS AND CONCLUSION: According to the theoretical analysis, and experimental research combined with the stable working range of the prototype, the system could generate axial fretting at tibial fragment and the bone fracture interface produced a certain mechanical stimulation under the conditions of excitation frequency of 26-40 Hz and excitation force of 100-350 N. Due to the omission of the stress shielding effect of the external fixator on the amplitude of the callus, the simulation results were slightly higher than the test results. The amplitude of the callus after disassembled was greater than that of the complete fixation. These results show that the stress-stimulator can make the tibial fragment to produce fretting which is beneficial to bone healing. In the clinic, it is recommended to use external stent with adjustable axial stiffness, constant external stiffness, which can effectively overcome the stress shielding. [ABSTRACT FROM AUTHOR]