The invention relates to an optical fiber array with an ultra-small core space. The optical fiber array comprises a substrate, optical fibers and a cover plate, wherein the front end of the substrate is provided with a limiting groove consisting of a plurality of groove bodies; the optical fibers are fixedly arranged in the groove bodies of the limiting groove; the cover plate is positioned above the optical fibers in the limiting groove; the optical fibers are anti-microbend optical fibers; the anti-microbend optical fibers are cladded and then arranged in the groove bodies of the limiting groove; the cladded optical fibers comprise an optical fiber region which can realize non-leakage light pass; a cladding at the region is thin and uniform. The device can be applied to the field of optical communication of high integration and can provide a plurality of light paths to realize light path coupling of the array channel or realize multiple cascading of the light paths in the device.