Due to the rapid development of industry and agriculture worldwide, water pollution has become the most important crisis facing humanity. Semiconductor-based photocatalytic method is one of the green technologies for controlling water pollution, which can effectively degrade and remove pollutants in water. The widespread use of metal oxide semiconductors in numerous photocatalytic materials, which stems from their salient features such as low toxicity, high stability, and resistance to chemical corrosion in aqueous solution. Among these, ternary metal oxides have surpassed other metal oxides in terms of photocatalytic activity under visible-light irradiation due to their reduced band gaps. This article systematically describes two typical ternary metal oxides-bismuth tungstate and bismuth molybdate. The preparation as well as the application and development of composite catalysts based on bismuth tungstate and bismuth molybdate in the field of photocatalytic degradation wastewater treatment are reviewed. The main problems in the design, mechanism research and modification methods of the composite materials on bismuth tungstate and bismuth molybdate are proposed, and the future development trend is prospected.