The　difference　of　corrosion　resistance　mechanism　between　alkali-activated　concrete　(AAC)　and　ordinary　Portland　cement　concrete　(OPC)　under　biogenic　sulfuric　acid　corrosion　was　compared.　By　measuring　the　local　surface　morphology,　mass　loss,　compressive　strength　and　Ca2+　dissolution　of　OPC　and　AAC　specimens,　the　corrosion　resistance　of　these　two　kinds　of　concrete　to　biogenic　sulfuric　acid　(BSA)　was　studied.　The　hydration　products　and　corrosion　products　of　OPC　and　AAC　were　studied　with　X-ray　diffraction　(XRD),　Fourier　transform　infrared　spectroscopy　(FT-IR)　and　environmental　scanning　electron　microscopy-energy　dispersive　spectroscopy　(ESEM-EDS).　The　results　show　that　under　BSA　corrosion,　the　thickness,　roughness　and　porosity　of　the　corrosion　layer　of　OPC　are　obviously　greater　than　those　of　AAC.　The　main　corrosion　products　of　OPC　and　AAC　is　gypsum.　The　amount　of　gypsum　produced　on　the　surface　of　OPC　corrosion　layer　is　larger　than　that　of　AAC.　In　addition,　the　bacterial　effect　on　the　surface　of　AAC　corrosion　layer　is　greater　than　that　of　OPC,　which　makes　the　corrosion　path　of　BSA　shorter　than　that　of　OPC.　Therefore,　the　corrosion　resistance　of　AAC　to　BSA　is　better　than　that　of　OPC.　©　2019　Elsevier　Ltd