Objective To simulate the internal structure of proximal tibia in both normal and valgus knees. Methods The internal structure of proximal tibia under normal mechanical environment was simulated using quantitative bone remodeling theory combined with finite element method. Based on this structure as the initial model and the changing pattern of pressure distributions on tibial plateau in valgus knee, the internal structure of proximal tibia in valgus knee was simulated with the action point of resultant force on the lateral tibial plateau. Results The simulated distributions of bone mineral density (BMD) were compared with the real tibia, and found the simulated results highly consistent with the actual ones both under normal mechanical environment and in valgus cases. Conclusions The method and the load distributions adopted in this study can accurately simulate and predict the internal structure of proximal tibia, thus could be served as the basis for further study on periprosthetic bone remodeling behavior after the total knee arthroplasty.