A recyclable magnetic triphenylphosphine ligand was prepared via a surface exchange reaction to load triphenylphosphine onto the surface of iron oxide nanoparticle with dopamine as a linker. The structure of magnetic nano-triphenylphosphine was characterized by IR, elemental analysis and TGA methods. The loading amount of triphenylphosphine on iron oxide nanoparticles could be elevated by increasing the ratio of dopamine-triphenylphosphine over nanoparticle and sonication time. Under the optimized condition, the triphenylphosphine content in the magnetic nano-triphenylphosphine ligand was 0.21 mol/mg. The magnetic nano-triphenylphsophine ligand could catalyze the hydroformylation reaction of styrene with Rh(OAc)2 as a Rh source and the in situ formed magnetic nano-triphenylphosphine-Rh catalyst could be recycled for 4 times under the optimum reaction condition with only 4.8% of triphenylphosphine dropped off from the nanoparticle surface. The optimum reaction condition of styrene hydroformylation was: 1.25 mL styrene, 30 mg nano-triphenylphosphine (0.0063 mmol TPP), 1.8 mg Rh(OAc)2, 12 mL THF, 3 MPa syngas (VCO:VH2 = 1:1), 90 °C, reaction time 9 h.