This work is to compare the experiment results by a continuous fixed-bed adsorption of water vapor, acetone vapor, and toluene vapor on zeolite 13X (SAU) and silica-alumina (SAK). SAU and SAK have very different pore structure but similar composition as inorganic adsorbent. The relationship between the equilibrium adsorption capacity and specific pore size range were studied. Adsorption of water vapor was more suitable on SAU than SAK because SAU has relatively more developed pores around $5;AA$ than SAK in the pore range of $10sim100;AA$. Adsorption of acetone vapor was more suitable on SAK than SAU because SAK has relatively more developed pores around $5sim10;AA$ than SAK in the pore range of less than $10;AA$. Adsorption of toluene vapor was more suitable on SAK than SAU because SAK has relatively more developed pores in the pore range of $10sim100;AA$ than SAK. Adsorption capacity of the adsorbent was closely related to the surface area generated in the specific pore size region. But it was difficult to distinguish the relationships between adsorption capacity and micro area, and the external surface area of adsorbent.