The invention discloses preparation and application of a dendriform TiO2-coating CdS hollow double-shell material. The preparation comprises the following steps: preparing a CdS-coating polystyrene core-shell material (PS@CdS) by adopting an ultrasonic wave assistance method, introducing CTAC, coating a TiO2 shell through a wet chemistry method to prepare the dendriform outer morphology (dendriform PS@CdS@TiO2), and sintering to remove polystyrene to obtain the target material, namely the dendriform hollow CdS@TiO2, wherein the dendriform hollow CdS@TiO2 has efficient light degradation performance for organic wastewater, especially RhB printing and dyeing wastewater under condition with visible light. The preparation conditions are mild, the method is novel, the operation process is simple, the treatment is rapid, the hollow double-shell material has good stability, photocorrosion generated by CdS is effectively avoided, the degradation capability during the recycling process is basically kept stable, the preparation and the application are economical and environmentally friendly, and the hollow double-shell material can be widely applied to degradation and recycling of other organic wastewater, especially deep degradation of organic wastewater with low concentration.