Semiconductor photocatalysis has become the focus of recent research on antibiotic treatment because it is a green and efficient technology. In this study, alpha-GaOOH with several novel microstructures has been synthesized at a low temperature and its subsequent thermal transformation. The influence of pH on the synthesis of alpha-GaOOH is studied, and the results indicate that pH played an important role in the microstructures of alpha-GaOOH and beta-Ga2O3. All Ga2O3 samples possess macro-mesoporous network structures and exhibits a remarkable photocatalytic activity for antibiotic degradation. The photoelectron chemical tests show that the separation efficiency of photogenerated charge carriers of Ga2O3-7.0 is higher than that of other Ga2O3. The enhanced photocatalytic activity of Ga2O3-7.0 is mainly ascribed to its morphology and oxygen vacancy. The active species trapping and photoluminescence measurement experiments indicate that (OH)-O-center dot and O-center dot(2)- are the major active species contributing to the photocatalytic process. This study will bring about the potential application in treatment of the antibiotic pollutants. (C) 2018 Elsevier Inc. All rights reserved.