Study of the photocatalytic activity of multi-walled carbon nanotubes/titanium dioxide nanocomposites MWCNTs/x%TiO2 with different weight ratios of TiO2 (x = 3, 6 and 10%) synthesized using a simple modified evaporation method in decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories was reported. The structure of the synthesized MWCNTs and MWCNTs/x%TiO2 nanocomposites with different weight ratios photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic technique and N2 adsorption-desorption. Also optical band gap was estimated by Kubelka-Munk equation for MWCNTs and MWCNTs/x%TiO2 nanocomposites giving rise values 3.51, 2.89, 2.80, 2.69 eV respectively. The photodegradation of Vat Green 1 and Dianix Blue Dyes dyes in presence of MWCNTs and MWCNTs/x%TiO2 nanocomposites after complete degradation were measured using chemical oxygen demand processes and the suggested possible mechanism of the photodegradation processes of Vat Green 1 and Dianix Blue Dyes was studied.