The paper deals with the experimental study on the effect of maldistribution on the break through in a technical column of activated carbon.The effect of maldistribution are described with a 2D model．The result shows that the effect of maldistrbution can not be neglected even when Db/dp=90．The difference of breakthrough between the wall-near zone and the center of the fixed bed can be 4 hours.The calculated results are in good agreement with the experimental ones.