As　one　of　the　most　destructive　and　widespread　disease　of　rice,　Magnaporthe　grisea　(M.　grisea)　has　a　significant　negative　impact　on　rice　production.　Therefore,　it　is　significant　to　develop　a　method　for　sensitive　and　high-throughput　detection　of　M.　grisea　in　order　to　help　farmers　to　find　and　control　blast　in　the　early　stage.　We　herein　first　cloned　and　expressed　the　M.　grisea＇s　chitinases　(Mgchi)　and　a　rice　cDNA　encoding　mannose-binding　jacalin-related　lectin　(Osmbl)　with　Mgchi-related　gene.　We　demonstrated　that　Mgchi　could　be　used　as　a　biochemical　marker　for　the　detection　of　M.　grisea　and　there　was　a　specific　interaction　between　Osmbl　and　Mgchi.　Using　Mgchi　as　biochemical　marker　and　Osmbl　as　recognition　probe,　we　developed　a　visual　method　for　the　specific　and　sensitive　detection　of　M.　grisea　based　on　the　PdNPs-catalyzed　TMB/H2O2　system.　The　proposed　method　could　be　used　to　detect　Mgchi　as　low　as　7.5×10-9M　by　naked　eye　observation　and　2.5×10-11M　Mgchi　by　the　micro-plate　reader.　With　the　help　of　the　method,　we　had　successfully　detected　M.　grisea　in　the　real　M.　grisea-infected　rice　plant　with　recoveries　of　88-109%　and　RSD