Background and Objective: Due to the water shortages and the presence of industrial pollutants in water resources, wastewater treatment, especially colored wastewater, is essential. The aim of this study was to treat wastewater containing Methylene Blue dye using activated carbon nanocomposite/zinc oxide nanoparticles (ZnO/AC) obtained from canola oil waste by green method. Materials and Methods: In the present study, the effect of different parameters (pH, Methylene Blue concentration, adsorbent amount, temperature and contact time) on the adsorption of Methylene Blue was investigated. design of Experiment 7 software (response surface Method (RSM)) was used to evaluate the influence of various parameters on Methylene Blue removal. Results: The results of the predicted experiments showed that the highest adsorption of Methylene Blue is at pH = 10, temperature 70 ° C, contact time of 50 min, initial adsorption concentration of 10 mg/ L and adsorbent amount of 0. 05 g. Under optimal conditions, ZnO/AC adsorbent was able to remove 98. 22% of Methylene Blue from the aqueous medium. Conclusion: Appropriate to the high potential of ZnO/AC nanocomposite in the removal of Methylene Blue pigment, it can be a good candidate for the removal of dye contaminants and wastewater treatment of textile factories.