Color is one of the most important contaminant factors of wastewaters such as textile, leather, dyeing and plastic industries, cosmetics, paper and paint industry and food industries. Present study was conducted with the aim of evaluating the efficiency of processed walnut bark powder for methylene blue color removal from aqueous solutions. The study was experimental- intervention type. In the study, initially walnut bark samples were milled and then sieved and 80×360 μm particles were separated and collected. In order to removing impurities, milled samples were rinsed several times by sodium bicarbonate detergent, 0.1 N HC and distilled water and dried at 105°C for 2 hours. For measuring absorption amount and color concentration spectrophotometric method was utilized at 663nm. Results showed that removal percent of methylene blue dye increased by increasing in dye initial concentration and contact time. Absorption data for studied absorbent follows Freundlich model with regression coefficient of R2= 0.93. Processed walnut bark powder as an inexpensive and possibility to preparation in different conditions could be utilized as strong absorbent for water and wastewater treatment. Strength of the present study could be utilization of inexpensive and easy biotechnology for environmental pollution.