The invention provides an optical mode cleaner, which comprises a three-mirror ring optical resonance cavity. The three-mirror ring optical resonance cavity comprises a cylindrical cavity (1), a pyrometric cone (5) and a circular bottom plate (10). One end of the cylindrical cavity (1) is connected with the pyrometric cone (5) and the other end of the cylindrical cavity (1) is connected with the circular bottom plate (10) to form a sealed integral cavity. A plane mirror (6) and a plane mirror (7) are respectively fixed on two inclined surfaces of the pyrometric cone (5). A concave mirror (8) and piezoelectric ceramics (9) are fixed in the center of the circular bottom plate (10). The resonance cavity is made of invar steel, a temperature control device is used for integrally controlling the temperature of the cavity, the entire cavity is sealed and the cavity is fixed on a V-shaped base in a way of line contact. The optical mode cleaner has high stability and narrow line width and can be used in aspects such as filtering extra noise of laser, improving light spot quality, improving the compression degree or entanglement degree of nonclassical optical fields, and the like.