The novel hierarchical sea-urchin-like Fe3O4/SnO2 heterostructures with SnO2 nanorod arrays grown on Fe3O4 nanoparticles were fabricated via a SnO2-seeded heteroepitaxial growth of SnO2 nanorod arrays on Fe3O4 nanoparticles. Moreover, the Fe3O4/SnO2 heterostructures showed notable photocatalytic degradation compared with the pure SnO2 in aqueous solution. The degradation reached 89% in 5h. The remarkable improvement in photocatalytic efficiency was ascribed to larger specific surface area introducing more active sites. In addition, the decline in degradation efficiency of p-chlorophenol is not more than 11.4% after recycling for seven times in accordance with practice which indicates the excellent repeated availability. The enhanced photocatalytic performance and features that can be easily recovered and separated make Fe3O4/SnO2 have great potential application in the environmental remediation.