Bamboo is an evergreen perennial plant, and it is known as one of the most productive and fastest-growing plants in the world. It grows quickly in moderate climates with only moderate water and fertilizer. Traditionally in Asia, bamboo is used for building materials, as a food source, and as versatile raw materials. Bamboo as a biomass feedstock can be transformed to prepare activated carbon using the thermal treatment of pyrolysis. The effect of process variables such as carbonization temperature, activation temperature, activation time, the amount of steam, and the mixing ratio of phosphoric acid and bamboo were systematically investigated to optimize the preparation conditions. Steam activation was proceeded after carbonization with a vapor flow rate of 0.8 ~ 1.8 mL-H2O g-char-1 h-1 and activation time of 1 ~ 3 h at 700 ~ 900 ℃. Carbon yield and surface area reached 2.04 ~ 20.59 wt% and 499.17 ~ 1074.04 m2 g-1, respectively, with a steam flow rate of 1.4 mL-H2O g-char-1 h-1 for 2 h. Also, the carbon yield and surface area were 24.67 wt% and 1389.59 m2 g-1, respectively, when the bamboo and phosphoric acid were mixed in a 1:1 weight ratio (700 ℃, 2 h, 1.4 mL-H2O g-char-1 h-1). The adsorption of methylene blue into the bamboo activated carbon was studied based on pseudo first order and second order kinetics models. The adsorption kinetics were found to follow the pseudo second order model, which is governed by chemisorption.