In terms of medicine- the inclined angle of femur- neck fracture section, the general description about the type of femur- neck fracture is given in this paper. For the case of three needle fixing methed, the functional relations of the deflection of the femur in the action of the vertical loads, the axial pressure and the shear with the inclined angle a are divided and the mono-tonicity of the functions are discussed. The inclined angle 2 is divided into three Limits(a<30°,30°70°)and each is discussed about the problem of the fracture fixing and beal. Finally, some measures are give for solving the fracture fixing unstable problem when a is larger. The above conclusions could be generalized to the cases of two needle fixing and four needle fixing.