In order to improve the spinnability and develop a potential application of konjac glucomannan (KGM), KGM grafted with styrene (St)/butyl acrylate (BA) (KGM-g-St/BA) was prepared via free-radical polymerization in this study. Subsequently, fibers of KGM-g-St/BA and core/shell poly(caprolactone) (PCL)/KGM-g-St/BA fibers were respectively obtained by electrospinning technique. The properties of KGM-g-St/BA copolymer and fibers were characterized by FTIR, TG, SEM, FE-SEM and TEM. The hydrophobic property of KGM dramatically increased after grafting modification. KGM-g-St/BA graft copolymer fiber film and core/shell fiber film have a good hydrophobic property.