The present study investigated the green synthesis of Cu2O on yellow phosphorus slag (YPS) in the presence of nonionic surfactant, Tween 80 and ascorbic acid. The weight ratio of YPS/Cu(NO3)2.3 H2O was varied to evaluate the effect of Cu2O nanoparticles content on the properties of hybrid YPS. The characteristics of the hybrid material were evaluated by FT-IR, SEM, HR-TEM, XRD, UV-Vis, EDX mapping and DLS methods. The obtained results indicate the successful synthesis of Cu2O nanoparticles (Cu2O-NPs) on the YPS surface, exhibiting a regular spherical shape and a particle size in the range of 10–50 nm. Both the calcium phosphate β crystals of YPS and cuprite crystals of Cu2O NPs were appeared on the XRD pattern of the hybrid YPS materials. The YPS and hybrid YPS materials was stable in water with a negative charge lower than −24 mV. The hybrid YPS materials exhibit a great bactericidal activity against both E. coli and S. aureus strains, especially at the ratio of 30% of Cu(NO3)2.3 H2O. The study also applied YPS-Cu2O for removal of anionic active dye Remazol midnight black (RGB) in water. Under optimal conditions by Box-Behnken model, including pH 6, adsorption time of 240 min and YPS-Cu30 mass of 0.04 g, the RGB adsorption efficiency using YPS-Cu30 reached the highest, with a RGB removal of 86.34 ± 0.34% and an adsorption capacity of 65.23 ± 0.25 mg.g−1. We indicate that the hybrid YPS/Cu2O is an excellent adsorbent for dye removal and antibacterial additive.