The invention discloses a production method of a micro nanometer fiber non-woven fabric and a device. The production method comprises the following steps: (1) polymer solution is prepared: (2) fiber is formed by micro nanometer jet injection: air pressure is supplied by an air pump, so the air stream is vertically sprayed out from a nozzle below the polymer solution liquid surface of a liquid storage tank, a crater-shaped projection is produced on the liquid surface of the polymer solution, the micro nanometer jet flow is sprayed out form the projection under the effect of the cutting force of the air stream and flies to a receiving device, during the injection process, good solvent in the micro nanometer jet flow is volatilized, and at the same time, the jet flow is drawn and refined to micro nanometer fiber under the effect of the air stream force; (3) and the non-woven fabric is formed. The production device is designed according to the production method and mainly comprises a spinning system, a liquid supply system, a transmission system and a control system.