The invention discloses a ring laser. The ring laser comprises a laser resonant cavity formed by a resonant cavity body, plane mirrors, E-type mirrors, air storage holes and a capillary pipeline, wherein a cathode, a large anode and a small anode are further arranged on the resonant cavity body; a process cathode is further arranged on the resonant cavity body; the process cathode and the cathode are symmetrically arranged on two sides of the resonant cavity body. According to the ring laser, the process cathode is symmetrically arranged on the opposite side of the cathode of the conventional ring laser to form a double-cathode double-anode electrode layout form, so that a discharge cleaning channel can be formed by utilizing the two cathodes and the large anode in a gas discharge cleaning process, another discharge cleaning channel is then formed by utilizing the two cathodes and the small anode, the plasma discharge cleaning strength of the capillary pipeline of the resonant cavity body can be remarkably improved, and the plasma discharge cleaning range of the capillary pipeline of the resonant cavity body can be remarkably expanded; compared with a single cathode, two cathodes are used at different times so as to effectively prolong the service life of a laser gyroscope.