Layered　La2Ti2O7　nanosheets　were　prepared　through　a　one-step　hydrothermal　method　at　low　temperature.　The　concentration　of　NaOH　mineralizer　plays　an　important　role　in　the　synthesis.　The　scanning　electron　microscopy　(SEM)　and　transmission　electron　microscopy　(TEM)　images　show　that　the　thickness　of　every　nanosheet　is　about　5-10　nm,　while　the　planar　dimension　is　more　than　1　mu　m.　The　photo-catalytic　activities　of　the　nanosheets　were　characterized　by　the　decolourization　of　methyl　orange　solution　and　the　evolution　rate　of　H-2.　The　results　demonstrated　that　the　La2Ti2O7　nanosheets　possess　significantly　improved　photocatalytic　properties　in　water　purification　and　evolution　rate　of　H-2　from　water-ethanol　solution　compared　with　those　of　samples　prepared　by　conventional　solid-state　reaction.