<p>Developing sustainable, environment-friendly, and highly efficient biomass photocatalytic hydrogels for degrading organic contaminants is a promising strategy to address the dual challenges of energy shortage and environmental pollution. In this study, BiOCl and PEDOT: PSS were incorporated into konjac glucomannan/ κ-carrageenan/polyvinyl alcohol (PKK) three-network hydrogel via facile mixing and cyclic freeze-thaw method to fabricate a multifunctional composite hydrogel for efficient photocatalytic elimination of Rhodamine B (RhB). The combination of BiOCl, PEDOT: PSS and PKK contributed to the boosted visible-light harvesting, decreased band gap energy, and provided a stable and porous bulk material, effectively addressing the problems of photocatalyst aggregation, limited recyclability and inferior regenerability. The physicochemical characterizations revealed the formation of hydrogen bonds between PEDOT: PSS and the alcoholic hydroxyl groups in PKK matrix, which not only promoted the uniform dispersion of BiOCl in hydrogel, but also effectively reinforced the mechanical properties of the composite hydrogel. Besides, the conductive polymer PEDOT: PSS can build electronic pathways between BiOCl and the hydrogel matrix to facilitate photogenerated carrier transport, enabling efficient charge separation. The BiOCl/PEDOT: PSS/PKK composite hydrogel achieved a degradation rate of 99.2% for RhB with 60&#xa0;min of visible light illumination. Furthermore, the degradation rate of RhB by BiOCl/PEDOT: PSS/PKK remained above 92% after five cycles of reuse, exhibiting its long-term stability and recyclability. Additionally, this composite hydrogel exhibits reversible swelling-shrinking behavior, which is conducive to the preservation and reusability of the photocatalytic hydrogel. This work offers a novel reusable biomass based photocatalytic hydrogel for wastewater treatment and a promising approach for the design of effective, reusable and green photocatalytic materials.</p>