This　study　reports　a　facile　approach　for　the　synthesis　of　horseradish　peroxidise　(HRP)-inorganic　hybrid　nanoflowers　by　self-Assembly　of　HRP　and　copper　phosphate　(Cu3(PO4)2·3H2O)　in　aqueous　solution.　Several　reaction　parameters　that　affect　the　formation　of　the　hybrid　nanoflowers　were　investigated　and　a　hierarchical　flowerlike　spherical　structure　with　hundreds　of　nanopetals　was　obtained　under　the　optimum　synthetic　conditions.　The　enzymatic　activity　of　HRP　embedded　in　hybrid　naonflowers　was　evaluated　based　on　the　principle　of　HRP　catalyzing　the　oxidation　of　o-phenylenediamine　(OPD)　in　the　presence　of　hydrogen　peroxide　(H　2O2).　The　results　showed　that　506%　enhancement　of　enzymatic　activity　in　the　hybrid　nanoflowers　could　be　achieved　compared　with　the　free　HRP　in　solution.　Taking　advantages　of　the　structural　feature　with　catalytic　property,　a　nanoflower-based　colorimetric　platform　was　newly　designed　and　applied　for　fast　and　sensitive　visual　detection　of　H2O　2　and　phenol.　The　limits　of　detection　(LODs)　for　H2O　2　and　phenol　were　as　low　as　0.5　μM　and　1.0　μM　by　the　naked-eye　visualization,　which　meet　the　requirements　of　detection　of　both　analytes　in　clinical　diagnosis　and　environmental　water.　The　proposed　method　has　been　successfully　applied　to　the　analysis　of　low-level　H2O2　in　spiked　human　serum　and　phenol　in　sewage,　respectively.　The　recoveries　for　all　the　determinations　were　higher　than　92.6%.　In　addition,　the　hybrid　nanoflowers　exhibited　excellent　reusability　and　reproducibility　in　cycle　analysis.　These　primary　results　demonstrate　that　the　hybrid　nanoflowers　have　a　great　potential　for　applications　in　biomedical　and　environmental　chemistry.　©　2014　American　Chemical　Society.