In recent years, substantial research has been carried out on 3D micro mirrors. Torsional micromirror is among the most interesting. After reviewing the recent development of torsional micro mirrors, this paper presents and studies a new design approach of 3D OXC torsional micro-mirrors. These devices are made by using CMP polishing method, wich offers a good surface flatness and don't suffer from the bottom layers conformality, encountered with the RIE etching used in some conventional surface micro-machining processes. The design is optimised by using FEM analysis method. The simulation results have contributed to the success of the tested MOEMS components. These micro mirrors provide larger integration density, enhanced flatness, larger deflection angle and lower driving voltage than current MEMS design