In this work, an elastomeric Fe3O4 nano-particles (NPs)/polybutadiene rubber (BR) composite membrane was prepared by using the combined technique of electrospinning and in-situ crosslinking. The results showed that the saturation magnetization (M-s) and the coercive force (H-c) of the electrospun composite membrane with 5 wt.% Fe3O4 NPs was increased by 21 % and 69 %, respectively, comparing with the membrane prepared by solution casting. This was ascribed to the fine nano-dispersion of Fe3O4 NPs in BR matrix by using the electrospinning and in-situ crosslinking technique because the re-aggregation of Fe3O4 NPs was largely restrained by the fast evaporation of solvent, the confined space of nano/micro-sized fibers and the rapid crosslinking during electrospinning. Our work demonstrated that electrospinning and in-situ crosslinking is a simple and efficient method to improve the dispersion of nanoparticles in an elastomer matrix, and thus prepare high performance elastomeric nanocomposite.