The large volume of water and chemicals, used in textile industry, causes the pollution load to become high, among the other industries. Among the pollutants, produced in this industry, dyes are more toxic than the others and their presence is more appeared in the environment. Due to high molecular weight and aromatic structure, reactive dyes that are used for cellulosic products are more toxic than other dyes. These dyes are highly soluble in water and cannot be easily removed by common wastewater treatments. For these reasons, in this study the removal of reactive dye from simulated wastewater was investigated. Among the methods that treat wastewater, using membrane filtration with nanofibrous membrane can be more effective than other methods. Because these membrane are too porous and the pores are inter connected. Also, they can be easily functionalized in nano scale. In this research, we first tried to use nanofibrous membrane, produced by electrospinning of 13% w/w PAN/DMF solution to remove C.I. Reactive Blue 13 from a simulated waste water. The dye concentration in the waste water was 0.2 g/l. Accordingly, the effect of various parameters such as the type of filtration system (dead end cross flow), time of electrospinning and applied pressure were analyzed. In cross flow filtration system with the applied pressure 1.9 bar, the decolorization efficiency of 16% was obtained. Investigating the duration of electrospinning showed that, four hours of electrospinning is suitable to obtain a higher efficiency. Alum was used as a coagulant to increase the color removal efficiency. In alum concentratio 1500 ppm, in conditions (stirring solution in terms of speed 1000 rpm, pH = 3.94, room temperature and suddenly adding) 79.25% decolorization efficiency was achieved. In the following, using cyclodextrins to functionalize nanofibers and improving the color removal efficiency of them, were investigated. Cyclodextrins are natural based materials that have cavity in their structure because of connected glucose units. Since the cavity of cyclodextrin is hydrophobic and can form inclusion complex with pollutant molecules, this material was used to functionalize the PAN nanofibers and increase decolorization efficiency of membrane by forming inclusion complex between dye molecule and cyclodextrin cavity. By electrospinning of PAN/?CDP solution for four hours and filtration the wastewater, the color removal efficiency 24% was obtained. But after filtration, ATR–FTIR spectra of membrane surface showed that cyclodextrins have exited from the surface. Hence, in the following, the beta cyclodexrin polymer was produced. This insoluble polymer was the production of cross linking beta cyclodextrin with citric acid at 140°C for 4 hours. Results of electrospinning and filtration of wastewater solution with nanofibrous membrane, prepared by 15, 25 and 50% w/w PAN/?CDP, showed the optimum concentration of beta cyclodextrin polymer wa 15% w/w and with this concentration and 4 hours electrospinning of PAN/?CDP solution, at applied pressure 1.9 bar, color removal efficiency 31.39% was achived. Thermal Gravimetery Analyze (TGA) of dye before and after filtration indicated that the degradation temperature of dye has been increased. Also, the presence of peaks, belong to channel crystal i X – Ray Diffraction (XRD) pattern of membrane after filtration, proved that the dye molecules exist in beta cyclodextrin cavity and form inclusion complex.