General approach to the design of MEMS process flow and mask layout relies on purely experience and prior knowledge of the similar devices. It is a quite challenging and hard task, since a variety of professional knowledge and iterative attempts are required. This paper puts forward a novel approach based on feedback-based expert system (FBES) to the auto-design of process flow and layout according to the abstract geometry description of MEMS device. FBES involves feedback verification facility on the basis of conventional expert system, and has shown significant superiority on applicability, flexibility, and expansibility in comparison with the latter, especially for MEMS process flow auto-design. This paper describes the representation of 3D geometry of device, framework of FBES, rules of MEMS process matching, and an example of layout autogeneration and process matching system.