A process for producing flexible MEMS thin film without a manufactured substrate applied in a MEMS manufacture specially includes a method of forming a component interface in the middle between a manufactured substrate and a MEMS thin film formed on the manufactured substrate as a basis, which component interface is so easily destroyed by an external force that the MEMS thin film produced by the mentioned process is easily separated from the manufactured substrate, and the separated MEMS thin film due to out of limitation from the manufactured substrate may be further processed in later working process to obtain a MEMS thin film with special structural features has flexibility and particularly has electrical circuits, micro structure, or MEMS components integrated and manufactured into inside or on its both sides.