Pure　In2O3　is　considered　as　an　efficient　methanol　steam　reforming　catalyst.　Despite　of　several　studies　in　the　past　decades,　the　mechanism　of　MSR　on　In2O3　is　still　not　fully　understood.　In　this　work,　a　periodic　density　functional　theory　study　of　the　initial　dissociation　of　methanol　and　water　over　the　In2O3　(110)　surface　is　presented.　The　activation　energy　barriers　and　thermochemistry　for　several　elementary　steps　are　reported.　It　is　found　that　the　energy　barriers　for　O?H　bond　cleavage　of　both　CH3OH　and　H2O　to　produce　CH3O　and　OH　species　at　a　surface　In-O　pair　site　are　very　low,　indicating　that　In2O3　(110)　can　facilely　catalyze　these　two　important　processes　at　low　temperatures.　In　addition,　the　subsequent　dehydrogenation　of　CH3O　to　CH2O　is　also　found　to　proceed　with　a　low　barrier.