The　Co@BN　core-shell　nanostructure　of　Co　core　and　boron　nitride　(BN)　shell　was　prepared　through　a　facile　onestep　thermal　treatment.　The　as-prepared　Co@BN　nanocomposites　exhibited　excellent　dye-sensitized　photocatalytic　hydrogen　evolution　activity　(13.78　mmol　h(-1)　g(-1))　with　visible　light　and　the　apparent　quantum　yield　was　1.15%.　The　enhanced　adsorption　of　EY　on　the　BN　shell　and　the　Co/BN　Schottky　junction　facilitate　the　tandem　transfer　of　photo-generated　carriers　to　the　Co　surface.　Moreover,　the　core-shell　interface　serves　as　a　nanoreactor　boosting　the　reduction　of　H+　to　H-2　on　the　Co　surface.　Additionally,　the　magnetic　recyclability　makes　Co@BN　favorable　for　its　practical　application.　This　work　extends　the　application　of　the　＂photocatalysis　under　shell＂　and　has　potential　in　dye-sensitized　solar　cell.