The paper aims to investigate the elastic-plastic deformation behaviour and the evolution of atomic migration in the local contact region of micro devices in micro electro-mechanical system (MEMS) from microscopic perspective. Therefore, it was studied that the deformations between sphere diamond probe and soft metal copper based on the mixed potential function of EAM and Morse by using the classical molecular dynamics method. It was found that the evolution of dislocation ring under loading process showed an interesting micro phenomenon that there were four stages on the evolution of dislocation ring was observed obviously, namely formal stage→growth stage→reproduction stage→maintenance stage. Furthermore, the arranged hexagonal structures were easily to take place the strong coupling effect around it, which resulting the configuration structure of edge dislocation and spiral dislocation were formed and emitted to the bottom of the base finally as loading exceed a certain point. In addition, the subsurface damage of copper bases became more serious than other places under nanoindentation process, followed by the migration and evolution of dislocation loops on both sides of the contact area between the probe and the substrate. The occurrence and evolution process of dislocation ring in copper bases has significance response features to measure the strength of plastic deformation on local contact region, and also is a good way to represent the intrinsic manifestation of subsurface damage on nano-contact area. This research results will have deeply insight on micro-scale contact deformation behaviors and plays an important role in designing micro-structures with excellent tribological properties.