Abstract: A new MEMS technology using the oxided porous silicon as sacrificial layers was presented. The porous silicon formed by electrochemical etching in HF should be stabilized porous structure by annealing at 300℃ in nitrogen atmosphere, and then oxided to SiO₂ with porous structure at 700℃.The oxided porous silicon can be etched in HF quickly to avoid the problem of etching porous silicon. The free standing membrane and cantilever are obtained by using this technology.