Abstract: As carriers of cells and growth factor, bone scaffolds play a key role in tissue engineering. To develop a more effective design technology of scaffold's micro porous structures, a microstructure modeling method focusing on the description of surface morphology and size distribution of cancellous bone is presented. In this method, triply periodic minimal surface and fractal geometry are combined firstly to construct the fractal pore-making element, according to the analysis of pore surface of real cancellous bone. Secondly, the dual countering method is used to subdivide the volume closed by the anatomical bone surface into hexahedral meshes, of which the positions of vertices conform to the pore size distribution of real cancellous bone; then the fractal pore-making element is mapped into the hexahedrons based on isoparametric transformation approach, so that the whole micro porous structure of scaffold corresponding to cancellous bone can be modeled. Finally, the results of case study show that the proposed method is effective and feasible. By virtue of this method, customized scaffold models for additive manufacturing can be constructed.