A novel chromium sulfide-cobalt oxide nanostructures and decorated on Polyethylene Glycol (PEG)-chitosan (CS) nanocomposites as catalyst was synthesized by a facile method, and characterized by XRD, SEM, UV-Vis and XPS spectrum. The as-prepared CrS-CoO/PEGCS composites represented the photo-decompose efficiency against the decomposition of basic dye (Rhodamine B (RhB)). The band gap of nano-catalyst was determined to be in the range of 2.61 to 3.32 eV. The introduction of CrS into CoO increased the photocatalytic performance slightly, and decoration of CrS-CoO on PEGCS, which indicated the highest photo-degradation performance. Under the light irradiation, the active species OH and O radicals were important active agents in the photocatalysis process. The CrS-CoO/PEGCS nanocomposites can maintain a stable photocatalysis performance after three cycles. Finally, the reaction mechanism of photo-degradation of RhB was put forward. The antibacterial test demonstrated the remarkable properties of CrS-CoO/PEGCS nanocomposites in this research.