Water　plays　a　crucial　role　in　organic　synthesis.　However,　diversified　functionalization　manipulated　by　water　is　still　rare　and　remains　unexplored.　Herein,　we　report　the　first　water-manipulated　protocol　to　achieve　the　diversified　functionalization　of　tetrahydro-beta-carbolines　(TH　beta　Cs)　in　an　open　flask　at　room　temperature　that　exhibit　a　broad　functional-group　tolerance.　More　water　leads　to　monoarylation,　while　less　water　leads　to　diarylation.　Further　one-step　transformation　afforded　oxidized　bis(indolyl)methanes,　eudistomin　U,　and　the　related　derivatives　in　satisfactory　yields.