Resource utilization through effective separation of complex wastes is of great realistic significance in water and wastewater treatment. Photocatalytic degradation is a powerful water treatment technology with strong oxidation, but has no selectivity in degradation of various coexisting contaminants. In this work, a cationic starch (St-CTA) with selective adsorption performance was used as a catalyst carrier, and a complex film composed of St-CTA and a popular catalyst, CdS, (CdS/St-CTA) was designed and fabricated using in situ formation method. This starch-based complex film was used to remove various organic dyes (alizarin green (AG25), methyl orange (MO), and rhodamine B (RhB)) from their single and binary dye solutions. CdS/St-CTA exhibited evident selective photocatalysis degradation of AG25 and MO in AG25/RhB and MO/RhB binary systems, respectively, and had nearly no effect on RhB. It was because that the cationic groups on RhB hindered its adsorption on St-CTA carrier. Differently, St-CTA can effectively adsorb anionic AG25 and MO due to electrostatic attractions, causing the following selective photodegradation. The selective degradation of CdS/St-CTA to AG25 and MO rather than RhB was unchanged under different pHs and aforementioned coexisted anions. Furthermore, this complex film did not require regeneration and could be reused directly without removal capacity loss after five recycles. Therefore, a new and simple strategy of “selective adsorption enrichment and then selective photocatalysis degradation” with general applicability was provided to realize the effective separation and recovery of target contaminants in water by photocatalytic degradation technology.