Objective To compare biomechanical characteristics of external fixator, Kirschner’s wire, elastic stable intramedullary nailing (ESIN) for fixing proximal humeral fractures in children by finite element method.Methods The CT scanning data from the healthy humerus of an 8-year-old patient with proximal humeralfractures were collected, and the image data were imported in Mimics 21. 0 to establish the rough humeralmodel, which was imported in Geomagic 2013 to construct the three-dimensional (3D) model of cancellous and cortical bones of the humerus. After the model was assembled with 3 fixators ( external fixator, Kirschner’swire, ESIN), it was imported in ANSYS 2019 to simulate the upper limb under quiet, abduction, adduction, flexion, extension, external rotation, internal rotation working conditions. The maximum displacement of the distal humerus, the maximum stress of the fixture, and the maximum displacement of the distal fracture surface were analyzed. Results The minimum values of the maximum displacement of the distal humerus in models fixed by external fixator, Kirschner’s wire, ESIN appeared under extension (2. 406 mm), external rotation (0. 203 mm), external rotation (0. 185 mm) working conditions, respectively. Conclusions External fixator is the most unstable fixation of proximal humeral fractures in children, and the biomechanical performance of ESIN is better than that of external fixator and Kirschner’s wire fixation