Core-shell　nanospheres　with　a　nanosize　Co3O4　core　and　a　periodic　mesoporous　organosilica　(PMO)　shell　were　fabricated　by　the　packing　and　self-assembly　of　nanosize　Co3O4　particles-surfactantorganosilica　complexes　based　on　the　S+I-　pathway　under　basic　conditions.　The　amount　of　Co3O4　nanoparticles　is　crucial　to　the　formation　of　core-shell　nanospheres.　The　obtained　nanospheres　possess　a　uniform　particle　size　of　130　nm,　a　high　surface　area　of　474.1　m(2)　g(-1)　and　a　large　pore　volume　of　0.68　cm(3)　g(-1),　which　are　highly　advantageous　to　the　immobilization　of　Microperoxidase-11　(MP-11).　The　presence　of　Co3O4　nanoparticles　could　enhance　the　activity　of　immobilized　MP-11,　probably　due　to　their　peroxidase　activity.