Herein, an electrospinning process of samarium complex-doped PMMAs was carried out to fabricate ultrafine fibers with a uniform diameter of about 230 nm. Under ultraviolet excitation, luminescence comparison between bulks and nanofibers verifies the existence of spectral reshaping, which alters the emission ratio of ligands to Sm³⁺; moreover, the effectiveness of electrospun fibrosis in enhancing the fluorescence emission is further identified in the case of Phen-containing. In addition, color tunability is achieved with the fluorescence changing from reddish-orange in bulks to near-white light in nanofibers. The nanosizing in rare-earth phosphors by electrospun fibrosis is proven to optimize the fluorescence properties, which provides a new route to develop the effective light-converting materials.