Abstract: The COD degradation and decolourization of wastewater containing RDX was studied by the processes of UV/TiO2, UV/TiO2/H2O2 and UV/TiO2/Fenton in a circulating slurry photocatalytic reactor with a low-voltage mercury lamp. The results showed that the most efficient process was UV/TiO2/Fenton and the least was UV/TiO2. The efficiency of these treatment processes was obviously impacted by the initial COD of wastewater. When the initial COD was less than 2 g/L, the COD and colourity could be up to effluent standard in 180 min and 90 min respectively.