Cr(VI) is both an environmental pollutant and a precious metallic resource. This study aims to explore the feasibility of preparing AgCl/Ag2CrO4 composite catalysts using Cr(VI)-containing soil washing effluent and analyze the key influencing factors during the process of the material's degradation of organic pollutants. The successful synthesis of the catalysts was confirmed by characterization techniques such as XRD、EDS, and XPS. Using methyl orange (MO) as the target pollutant, the effects of preparation conditions, including the concentration of precipitants and the reaction temperature, on the utilization rate of Cr(VI) and the photocatalytic performance of the catalysts were investigated. Also, the impacts of the catalyst dosage, the initial concentration of MO, and the pH value on the degradation effect of MO were examined. The results show that the optimal preparation condition is uniformly dropwise to add 0.1 mol/L AgNO3 precipitant at 25 °C, under which the composite catalyst exhibits the strongest photocatalytic performance, and the concentration of Cr(VI) in the residual liquid after catalysts synthesis is lower than the limit (≤ 0.5 mg/L) specified in the Integrated Wastewater Discharge Standard GB8978-1996. When the initial concentration of MO is 20 mg/L, the catalyst dosage is 0.7 g/L, and the pH value is 6.28, the degradation rate of MO reaches 88.1%. In addition, this catalyst also has photocatalytic performance for rhodamine B and methylene blue. Therefore, this study realizes the concept of “treating waste with waste” for resource recycling, and provides a theoretical basis and research ideas for the pollution control and resource utilization of heavy metals and organic wastewater.