The confined etchant layertechnique (CELT) has been proved an effective electrochemical microfabrication method since its first publication at Faraday Discussions in 1992. Recently, we have developed CELT as an electrochemical mechanical micromachining (ECMM) method by replacing the cutting tool used in conventional mechanical machining with an electrode, which can perform lathing, planing and polishing. Through the coupling between the electrochemically induced chemical etching processes and mechanical motion, ECMM can also obtain a regular surface in one step. Taking advantage of CELT, machining tolerance and surface roughness can reach micro- or nano-meter scale.