Rice hull was calcined to rice hull ash (RHA) at 500 degrees C under 20 mL air s(-1) for 50 min. The RHA thus prepared has been found to adsorb nickel (II) ion from aqueous solution efficiently. Experimental results indicated that the rate of adsorption of nickel ion and the adsorption of nickel ion at equilibrium were increased upon decreasing RHA dosage. They were also increased with increasing initial nickel concentration or adsorption temperature. On the other hand, they were found to remain unchanged when the initial pH was increased from 2.3 to 5.6, or the stroke speed was changed in the range of 30-180 stoke min(-1). The kinetic data obtained obeyed the pseudo-second-order rate equation. An empirical equation correlating the relationship between the adsorption of nickel ion and the adsorption time was also determined.