The invention discloses a micro electromechanical resonator based on a structural self-excited vibration principle, which comprises an insulation support pedestal, a conducting micro beam, two direct current driving electrodes and a substrate, wherein the insulation support pedestal is neither connected with any electrode nor grounded, that is electric potential is floating; one end of the conducting micro beam is fixed on the insulation support pedestal; the other end of the conducting micro beam is horizontally overhung; the two direct current driving electrodes are placed on the two sides of the conducting micro beam; one of the direct current driving electrodes is connected into direct current positive voltage; the other direct current driving electrode is connected into direct current negative voltage; a certain distance is kept between the two direct current driving electrodes; and the insulation support pedestal and the direct current driving electrodes are fixed on the substrate. The micro electromechanical resonator abandons a complicated alternating current driving/detection circuit essential to the traditional resonator, and eliminates a short circuit risk arising from structure destabilization; a structure is simplified; and resonance amplitude is increased greatly.