Objective To investigate stress changes following application of Gamma nail in modally body.Method Gamma nail was placed femur in isolated intertrochanter fracture.Pressure test was made using Almighty Material Testing machine under static and dynamic state and standing with single leg to learn about secondary fracture,bending of machine,flexion,penetration of femoral head,disjunction of fracture line and so on.The results were compared with those of goose head nail fixationa and normal femur.Result Under static pressure,Gamma nail can better endure pressure of 2 000 N compared with goose head nail,disjunction of fracture line was less than 0.9 mm for Gamma nail.There was no evident difference in moving down of the femoral head between Gamma nail and goose head nail.Gamma nail can endure body weight.Conclusion Gamma nail is designed based on mechanics,and can endure body weitht and be applied for various intertrochanter fracture.