Abstract: To thoroughly utilize rice husk resources and obtain high absorbable activated carbon, rice husk ash (RHA) was desiliconized and activated with NaOH as the desiliconizer and KOH as the activator, respectively. Single factor analysis and orthogonal test design were used to determine the effects of carbon-alkali ratio, activation temperature and activation time on the adsorption property of activated carbon with the absorptive value of methylene blue as the index to establish the preparation process of high absorbable activated carbon. The results showed that the optimal combination of activation process parameters were as follows: carbon-to-alkali ratio 1∶3, activation temperature 550 ℃, activation time 40 min. Factors affecting the adsorption of activated carbon was in this order: the ratio of carbon to alkali> activation temperature> activation time. Based on the adsorption-desorption isotherm, the activated carbon isotherm belonged to type IV, and the carbon had advanced micropore and mesopore structure. Scanning electron microscope (SEM) was used to determine the pore size and pore volume of activated carbon. The results showed that activated carbon with high specific surface area and high adsorption could be prepared by KOH activation method. X-ray diffraction (XRD) was used to observe the microcrystalline structure of rice husk ash, desiliconized rice husk ash and activated carbon, it was found that there were diffraction peaks around 2θ=22.3°, 2θ=24.0°, and 2θ=24.4°, respectively, indicating that the activated carbon prepared by rice husk ash had an amorphous structure.