For optimal usage of metallic nanostructures in various industrial applications, it is critical to obtain fundamental understanding of deformation and failure mechanisms at micron- and sub-micron length scale, where individual defects could play critical roles in exhibiting macroscopic mechanical properties. However, understanding the fundamental deformation mechanism for these novel nanomaterials remains intriguing due to intricate interplay of various geometric characteristics and intrinsic microscopic defects. To investigate deformation mechanism at small scale, nanomechanical defect dynamics modeling techniques have been developed by coupling conventional finite element (FEM) with a discrete defect (DD) modeling. While the detailed defect microstructure and short-range interaction is handled by DD framework, the long-range elastic interactions with image stress field are calculated by CPFEM (using commercial package (ABAQUS) with user-subroutine), accounting for complex boundary conditions. Our model could account for complex multi-physical phenomena, which would play an important role in obtaining a fundamental understanding of deformation mechanism at small scale. The developed model will shed light on fundamental investigation of “defect-controlled” mechanical behaviors in crystalline materials, such as plasticity and failure.