This research aims to study the effect of impregnation ratio and activation temperature on microporous development of activated carbon (AC). Rubberwood chips, which are wasted from home furnishing industry, were used as precursors for synthesized of activated carbon by chemical activation employing Potassium hydroxide (KOH) as activation agent. Rubberwood char was carbonized at 400 °C for 1 h under inert gas. In this experiment, the rubberwood chars were impregnated with KOH solution by 1:1–3 (char: KOH) impregnation ratio for 24 h, then the samples were activation at 600–800 °C. Surface area, pore volume, micropore volume, pore size distribution, adsorption isotherm and porous structure were analyzed in this experiment to identify the properties of derived activated carbon. According to the investigation, the activated carbon, activated at 800 °C with impregnation ratio of 1:3, demonstrated the highest surface area, pore volume and micropore volume as 1491.75 m2/g, 0.6777 cm3/g, and 0.5813 cm3/g, respectively. Its average pore size was 1.82 nm and it also showed type I adsorption isotherm which indicates as microporous solid.