Using non-noble metal catalysts to chemoselectively reduce the 3-nitrostyrene into 3-vinylaniline is extremely attractive due to the important applications of aromatic amines. However, the separation and recycle of catalytic particles to sustainably catalyze are still challenging on account of their small size. In this communication, we report a novel magnetically recyclable catalyst of Sm₂Co₁₇/Cu to chemoselectively reduce 3-nitrostyrene into 3-vinylaniline by activating ammonia borane (AB) to yield hydrogen. The Sm₂Co₁₇/Cu, composited of 180 nm Sm₂Co₁₇ nanomagnet and 10 nm Cu catalyst nanoparticles, shows a high conversion (98%) and a high selectivity (99%) for 3-nitrostyrene under ultrasonic concussion. More importantly, they are easily collected by self-separation method without any magnetic field. As a consequence, the excellent recyclable feature is acquired even underwent 10 cycles. Our approach provides a green strategy to synthesize magnetically recyclable catalysts.