The invention discloses a passive-phase-locked fiber ring laser, which relates to a fiber laser and overcomes the shortcomings of wideband output laser, system complexity and low output power of the conventional laser. N wavelength division multiplexers and N couplers of the laser are distributed on a ring at intervals, and are connected by N fiber Bragg gratings and N active single mode fibers. N pump sources are connected with the N wavelength division multiplexers respectively. One ends of the N single mode fibers are connected with the N couplers respectively, and the other end faces of the N single mode fibers are positioned in the same plane, and are arranged into a line, a hexagon, a rectangle or a triangle. The pump sources input pump energy into the active single mode fibers through the wavelength division multiplexers, generated laser signals are output by the single mode fibers connected with the couplers, and a plurality of paths of laser are coherently synthesized, so that narrow frequency spectrum and high power are ensured. The passive-phase-locked fiber ring laser is applied in the fields of industrial machining and national defense.