Dyes are an important in synthetic organic compounds. Are used in large quantities in the textile industries, plastic, cosmetic and tanning, etc. Use of indigoid dyes in textile finishing processes experienced in recent years a strong increase, causing a large volume of wastewater loaded with these dyes. Their release into aquatic systems without any prior treatment causes damage to the environment due to their toxicity, which requires treatment with suitable techniques that respect the environment. However, the complexity of these pollutants and their color greatly affect the effectiveness of treatments applied conventionally. Discoloration tests wastewater of textile industry and some colored solutions were carried out by the ultrafiltration membrane method. During this work, we synthesized a microporous asymmetric membrane alloy polysulfone and polyvinyl chloride. The objective of this work is to show the feasibility of the purification of industrial wastewater charged with indigoid dyes by ultrafiltration technique, using a new organic asymmetric membrane based on a mixture of two thermoplastic polymers, which are polysulfone (PSU) and polyvinyl chloride (PVC). From the results obtained in this work, it is found that the fading rate of the order of 89% corresponds to a membrane pressure of 20 cm Hg, in a basic medium at a pH of 11.80. According to this study, it appears that the operation of this asymmetric membrane based mixture (PSU and PVC) is very effective for the discoloration of a water solution of indigo dyes loaded with.