Monolayer　2H-MoS2　has　been　widely　noticed　as　a　typical　transition　metal　dichalcogenides　(TMDC)　for　surface-enhanced　Raman　scattering　(SERS).　However,　monolayer　MoS2　is　limited　to　a　narrow　range　of　applications　due　to　poor　detection　sensitivity　caused　by　the　combination　of　a　lower　density　of　states　(DOS)　near　the　Fermi　energy　level　as　well　as　a　rich　fluorescence　background.　Here,　surfaced　S　and　Mo　atomic　defects　are　fabricated　on　a　monolayer　MoS2　with　a　perfect　lattice.　Defects　exhibit　metallic　properties.　The　presence　of　defects　enhances　the　interaction　between　MoS2　and　the　detection　molecule,　and　it　increases　the　probability　of　photoinduced　charge　transfer　(PICT),　resulting　in　a　significant　improvement　of　Raman　enhancement.　Defect-containing　monolayer　MoS2　enables　the　fluorescence　signal　of　many　dyes　to　be　effectively　burst,　making　the　SERS　spectrum　clearer　and　making　the　limits　of　detection　(LODs)　below　10(-8)　M.　In　conclusion,　metallic　defect-containing　monolayer　MoS2　becomes　a　promising　and　versatile　substrate　capable　of　detecting　a　wide　range　of　dye　molecules　due　to　its　abundant　DOS　and　effective　PICT　resonance.　In　addition,　the　synergistic　effect　of　surface　defects　and　of　the　MoS2　main　body　presents　a　new　perspective　for　plasma-free　SERS　based　on　the　chemical　mechanism　(CM),　which　provides　promising　theoretical　support　for　other　TMDC　studies.