A　series　of　mixed-phases　TiO2　is　fabricated　via　a　mild　hydrothermal　process　using　titanium　trichloride　as　the　Ti　source　and　ammonia　water　for　regulating　the　ratio　of　anatase,　rutile,　and　brookite.　As　a　result,　TiO2　nanocrystals　comprised　of　anatase/brookite,　anatase/rutile/brookite　and　anatase/rutile　phases　can　be　obtained.　The　longest　optical　edge　is　observed　for　triphase　TiO2　system　among　all　of　the　as-prepared　samples　in　UV–vis　absorption　spectroscopy.　However,　the　results　for　the　photodegradation　of　levofloxacin　indicate　that　the　diphase　TiO2　(A61B39)　shows　higher　degradation　ratio　of　levofloxacin　instead　of　triphase　TiO2.　The　reasons　for　these　are　attributed　to　the　lowest　recombination　rate　of　photoinduced　charges,　the　most　negative　of　flat　potential,　and　the　larger　specific　surface　area　(SBET　=　101　m2/g)　for　A61B39　sample,　which　are　demonstrated　by　photoluminescence　spectra,　Mott-Schottky　plots,　and　N2　adsorption-desorption　isotherms.　Besides,　the　intimate　interfacial　structure　of　different　phase　can　be　observed　from　high　resolution　transmission　electron　microscopy,　which　contributes　to　charge　transfer.　Meanwhile,　the　photodegradation　mechanism　of　levofloxacin　over　A61B39　is　expounded.　This　work　demonstrates　a　facile　method　to　regulate　the　phase　ratio　of　TiO2　and　facilitate　its　application　in　environmental　remediation.　©　2020　Elsevier　B.V.