We reported that we developed the air permeability tester with which we could measure the acceleration of the air permeability (AAP) of coated paper under high temperatures and high pressures during a short time.And we found that AAP was more strongly related to the blistering tendency of coated paper.In this paper, we used various commercial A 2 web offset coated papers, and studied on the blistering resistance.Then we found that the internal bond of coated paper and AAP that had a direction from base paper to coating layer, was strongly related to the blistering tendency.So.the result indicated that the direction of the air permeability from base paper to coating layer was important to understand the blistering phenomenon.