Objective To investigate the effects of three different modelling approaches on biomechanical properties of the hip finite element model, and to investigate a more realistic method for assigning material properties to the hip joint. Methods The hip joint model was reconstructed in three dimensions, and the material parameters were assigned using the cortial bone and cancellous bone assignment method, the homogeneous assignment method and the gray value assignment method, respectively. The same boundary conditions and loads were set, the stress on hip joint during standing on one leg was simulated, and the stress and deformation of hip joint in three groups of models were compared. Results The hip stresses were concentrated in the medial femoral neck under three different modelling approaches, and the peak von Mises stresses were 11. 04, 3. 91 and 4. 25 MPa under the cortical bone and cancellous bone assignment method, the homogeneous assignment method and the gray value assignment method, respectively. The maximum deformation in hip model under cortical bone and cancellous assignment was at the upper part of the greater trochanter, with the maximum deformation value of 0. 27 mm at the acetabulum and femoral head. The maximum deformation in hip model under the homogeneous material assignment method and the gray value assignment model was at the acetabulum and femoral head, with the maximum deformation values of 0. 11 mm and 0. 12 mm, respectively. Conclusions The gradient assignment based on gray value of the hip CT data makes material property distributions of the hip model closer to real material properties of the bone.