Objective Clutching internal fixtor (CIF) loose and the fixed part weakly heal up are often found in orthopedic clinic.In the present paper, biomechanics methods were used to try to explain and analyze these issues, provide a helpful suggestion for the application of CIF in clinic. Method Commercial finite element method(FEM) Program ANSYS was applied to set up the Finite Element Models of orthopedic CIF and bone tissue to analyze and evaluate the biomechanical performances of the Ni Ti shape memory alloy CIF. Results There is an interaction force between embracing force of CIF and resistant force of bone tissue during the orthopedic clinical treatment. The embracing force along two semi-circular arms of CIF is increasing from the open position and reached the maximum value at the open symmetry position where the deformation of the bone occurre. Conclusion It is the key to choose the force loading position during the practical treatment, as the concentration force is the main force when there is an interactive force between the bone and the CIF.