Adsorption/desorption behavior and simultaneous heat and mass transfer in a honeycomb adsorber were investigated using a humidity chart, It was found that the dehumidifying performance is sometimes decreased remarkably owing to the mass/heat balance limitation when the feed humidity is high or regeneration temperature is low. A prediction method is proposed for the design principle of honeycomb adsorbers by taking into account the optimal rotation speed and the regeneration air velocity obtained from the graphical solution using a humidity chart, The method is simple to use, without complicated computation and it is useful to avoid the serious influence of by the mass/heat balance limitation, At a process air velocity of 1m/s, by considering the relation between the optimal rotation speed and the moderate regeneration air velocity obtained using a graphical method, the product air humidity decreases to a value near to the thermodynamic limit.