The invention relates to an optical fiber of coupling a multilayer rare earth blending ring-shaped fiber core with a single-mold fiber core, belonging to high-power optical fiber amplifiers, lasers and special fibers; a rare earth blending ion core area (1) is arranged at the center of the optical fiber, a first silicon ring core (21), a first rare earth blending ion ring core (41), ...(N+1)th silicon ring core (2, N+1), and a coating layer (3) are sequentially arranged from inwards to outwards, wherein, N is more than or equal to 2 and is less than or equal to 50; the refractive indexes of the rare earth blending ion core area, the first rare earth blending ion ring core, ...and the Nth rare earth blending ion ring core (4N) are equal, the refractive indexes of the first silicon ring core, ...and the (N+1)th silicon ring core are equal, the refractive indexes of the first silicon ring core (21), ...and the (N+1)th silicon ring core are lower than the refractive indexes of the rare earth blending ion core area, the first rare earth blending ion ring core, ...and the Nth rare earth blending ion ring core; the refractive index of the coating layer is lower than the refractive indexes of the first silicon ring core, ...and the (N+1)th silicon ring core (2, N+1), the manufacturing difficulty of the optical fiber is reduced, and large and effective mold area of the optical fiber is realized.