In the present paper, the effect of specimen geometry and voxel resolution on the mechanical characteristics of vertebral trabecular bone models was analyzed. Three dimensional (3D) micro finite element (micro-FE) method, based from high-resolution images (21-126μm), has been introduced to analyze trabecular bone structures in detail. Recently, considerable amount of work has been done to investigate the elastic characteristics of trabecular bone by using micro finite element model based on micro-computed tomography (μ-CT). However, there were few micro-FE models to account for the plastic characteristics of trabecular bones. In the present study, the micro-FE analyses were carried out for the plastic characteristic as well as the elastic characteristic of vertebral trabecular bone models using micro FE techniques and μ-CT. Also, one of the aims of the present study was to examine the effect of the micro-CT image resolution on the plastic characteristics of the micro-FE models for vertebral trabecular bones. The results illustrate that in the simulated compression test to analyze mechanical characteristics of vertebral trabecular bones, it is recommended to use a cubic specimen with side length 6.5mm and a cylindrical specimen (with diameter=7mm, length=5mm) rather than a cubic specimen with side length 4mm.