Mesoporous mixed-phase Ga2O3 was synthesized by calcining the GaOOH precursor. The composition, crystal phase and microstructures of Ga2O3 were characterized in detail. The phase composition of the as-prepared Ga2O3 depended on the calcination temperature and the mixed-phase Ga2O3 was obtained at 600-700 degrees C. As compared to the pure-phase alpha-Ga2O3 and beta-Ga2O3, the mixed-phase Ga2O3 exhibited an enhanced photocatalytic property for the degradation of metronidazole solution. The heterojunction in the mixed-phase Ga2O3 was beneficial to the separation of photogenerated electrons and holes. Moreover, the mixed-phase Ga2O3 possessed mesopore structure, which increased more reaction sites and was in favor of the contact of metronidazole molecules with reaction sites. The recycling experiments show that the mixed-phase Ga2O3 has good stability and can be separated easily from the reaction system. (C) 2015 Elsevier Ltd. All rights reserved.