Objective: in this study, three-dimensional finite element analysis of femoral head was conducted based on the classification of three-column structure china-japan Friendship Hospital (CJFH), to study the force on femoral head with different necrotic volumes, so as to provide theoretical basis for clinical hip preservation therapy.Methods:Select normal 25 young men hip CT slice, using Mimics, Geomagic studio, solidwork preliminary modeling, according to the theory of the three pillars in the solidwork divided area, set up blank control volume 0% necrosis, and aims at CJFH parting every type of set up 5% of the total volume femoral head, 15%, 30%, 50% of the necrotic volume model, a total of 22 groups of model, and in turn into ANSYS, based on the actual hip stress distribution and the subjects of the actual weight, set up stress position, and set up the contact relationships,Mechanical analysis was carried out after grid division.Results: according to the cloud picture and data of the displacement of the femoral head necrosis tissue displacement is larger, the displacement peak both in the necrotic tissue of weight-bearing area, different necrosis necrosis with mechanical volume distribution can be found that the dead volume is less than 15% of cases, pressure peak collapse pressure has not been achieved, when the dead volume reaches 30%, the L2 and L3 collapse risk is extremely high, L3 type with more than 50% necrosis area stress is greater than the failure stress.Conclusion: 3 d finite element study of ischemic necrosis of femoral head to help clinicians more intuitive, more three-dimensional observation of focal necrosis, it can be seen through the study of the mechanics analysis of focal necrosis of the necrotic tissue volume, the greater the displacement is larger, the more easy to collapse, when it comes to the necrosis of the lateral column volume of 30%, greatly increase the collapse probability.It was found that the stress was concentrated at the junction of necrotic bone and cortical bone.According to the actual situation of necrosis, hip preservation intervention, early detection and early treatment can effectively avoid the progressive aggravation of femoral head necrosis.