The　use　of　methyl-tert-butyl　ether　(MTBE),　which　is　a　gasoline　additive　to　enhance　the　octane　rating　of　gasoline,　has　resulted　in　increasing　pollution　of　groundwater.　Most　of　the　conventional　treatment　technologies　are　inefficient　or　expensive　due　to　its　high　solubility　in　water　and　low　Henry＇s　law　constant.　To　find　an　ecology　friendly　and　inexpensive　method　for　MTBE　remediation,　homemade　titanium　dioxide　MOO　was　used　as　a　photocatalyst,　and　the　photocatalytic　degradation　of　MTBE　in　a　batch　TiO2　slurry　reactor　was　studied　by　using　Purge　&　Trap　G-C-MS-SIM　and　IC.　It　was　showed　that　MTBE　can　be　photocatalytically　transformed　to　innocuous　products　and　mineralized　ultimately　in　oxygenated　TiO2　slurries.　The　major　by-products　of　this　reaction　have　been　identified　as　t-butyl　formate,　t-butyl　alcohol　and　acetone,　all　of　which　are　also　readily　degraded　photocatalytically,　albeit　at　different　rates.　Based　on　identification　of　intermediates　and　products,　the　first　step　in　the　destruction　of　MTBE　is　thought　to　be　abstraction　of　an　a-hydrogen　by　.OH　and　a　reaction　scheme　is　proposed.