The invention provides a film harmonic oscillator realization device of a high-mechanical-quality factor. The device comprises a metal fixed framework (1), optical fiber micro beams (2) and a film chip (3), wherein the metal fixing framework (1) is of a square plate-shaped hollow structure; two parallel narrow grooves vertical to the side frame are carved in the front surface of the upper and lower side frame, and are used for fixing the optical fiber micro beams (2); the optical fiber micro beams (2) are two micro optical fibers fixed on the metal fixed framework (1) after the tension exertion, and are separated into four equal-length optical fiber micro beams by the film chip (3). On the basis of a principle that an oscillator of the optical fiber micro beams (2) leaving far away from the harmonic frequency can be used as a sound wave filter, the phonon tunneling loss of the film chip (3) is effectively inhibited; the mechanical quality factor of the film oscillator is improved; the structure is simple; the cost is low; good mechanical performance can be maintained in the room-temperature vacuum and low-temperature vacuum environment; the film harmonic oscillator realization device can be applied to the fields of quantum optomechanics and the like.