Molybdenum　disulfide　(MoS2)　has　received　tremendous　attention　due　to　the　earth-abundant　composition　and　high　catalytic　activity.　However,　the　catalytic　activity　of　MoS2　except　electro-　and　photocatalytic　has　seldom　been　explored.　Herein,　Fe3O4@MoS2　core-shell　composites　were　prepared　for　the　first　time　by　in　situ　growth　of　MoS2　nanosheets　on　the　surfaces　of　Fe3O4　nanoparticles　under　different　temperature,　and　the　catalytic　performance　of　the　resulting　composites　was　evaluated　by　using　the　catalytic　reduction　of　4-nitrophenol　to　4-aminophenol.　FE-SEM,　TEM,　XRD,　and　XPS　analyses　verified　the　core-shell　structure　with　MoS2　nanosheets　of　defect-rich　and　oxygen　incorporation　on　the　surfaces　of　Fe3O4　nanoparticles.　Fe3O4@MoS2　composites　were　found　to　exhibit　a　high　catalytic　activity　for　the　reduction　of　4-nitrophenol　with　the　highest　activity　factor　k　=　3773　min-1　g-1.　A　plausible　catalytic　mechanism　for　the　reduction　of　4-nitrophenol　was　also　proposed.　This　study　presents　an　inexpensive,　reusable,　fast,　and　highly　efficient　catalyst　for　the　reduction　of　4-nitrophenol　without　noble　metals.　©　2015　American　Chemical　Society.