Objective To explore the influence of topical biomechanical environment in the fracture point after which was fixed with auto control micro motion locking nail (AMLN) on the fracture healing mode. Methods Twenty eight femoral shafts of fourteen sheep were fractured transversely and were fixed with AMLN or GK nails respectively. The animals were sacrificed at time point of one, two, four and eight weeks. The bony stiffness and intensity ,stress level in different fractural healing period and the rate of stress covered were measured. The mechanism of macro-and micro biomechanics in different fractural healing period were observed. Results ①The intensity of anti compression, anti flexion and anti-torsion in the fractural end after which fixed with AMLN is better than that fixed with GK nail. ② The stress level in the fractural end fixed with AMLN could recover completely at seven to eight weeks, which was four weeks earlier than GK nail fixation . ③ The rate of stress covered in the fractural end after which fixed with AMLN decline forty percent at initial stages, eighteen percent at metaphase and sixteen percent at advanced stage. Conclusion The design of AMLN accord with the guide line of plastic fixation. The geometry non anamorphosis which was constituted by the fixation set and the fractural far and near end was very firmly and settled. This fixation's disturbance to physical stress distribute in the fractural end was very lightly. AMLN fixation of fracture could resolve the balanced question between the stress conduct and the stress protection, it also could make the fracture end healing better, and make the fractural healing process speed up.