In this study, the Cu MoS /WO supported on chitosan was prepared by precipitation method, and applied to photocatalyst, antibacterial agent and biosensor. The presence of WO and Cu MoS crystals were confirmed by XRD analysis. The elemental information was investigated by EDS. FTIR spectra shows the presence of chitosan in nanocomposites. The as-synthesized Cu MoS /WO /Chitosan nanocomposites has a bandgap of 2.18 eV and it is effective for visible light condition. The average particle size of the Cu MoS /WO /Chitosan is 71 nm. The photocatalysis activity Cu MoS /WO /Chitosan was higher than Cu MoS or WO .The Cu MoS /WO /Chitosan nanocomposites shows the highest efficiency (100%) in photocatalysis degradation of dye under visible light irradiation in 80 min. The •O plays a main role in degradation process. The as-synthesized Cu MoS /WO /Chitosan nanocomposites depicted the antibacterial activity toward G+/- bacteria. Determination of enterococcus faecalis is important for human health. The DNA template was used to the Cu MoS /WO /Chitosan nanocomposites and applied in detection of enterococcus faecalis by H O and 3,3',5,5' -tetramethylbenzidine in peroxidase like activity. The detection limit of enterococcus faecalis by DNA-Cu MoS /WO /Chitosan in peroxidase-like catalysis was about 55 CFU/mL. Therefore, the Cu MoS /WO /Chitosan can be applied in the photocatalysis, bactericidal and peroxidase process.