The invention discloses a micro-resonance electrometer based on bending beams having single free ends and a charge detection method. A ground electrode, a substrate, a resonator, a drive electrode, asense electrode, an input electrode, and an anchor end are arranged inside the sensor. Two ends of two bending beams arranged at the resonator are connected mutually to form a fixed end and a detection end; the fixed end is connected with the ground electrode; the detection end is connected with the anchor end by a flexible support beam; and the detection end and the input electrode form a flat plate type input capacitor. Two sides of flat electrodes of the bending beams, together with the drive electrode and the sense electrode, forms a drive capacitor and a sense capacitor. According to theinvention, on the basis of the provided novel design of the bending beams with single free ends, the resonator works in an elastic deformation mode and a novel charge sensing mechanism is provided based on the elastic deformation mode, so that the high sensitivity is realized. Moreover, the nonlinearity influence of the resonator is eliminated and the temperature drift coefficient of the frequencyis reduced.