In the previous study, the analysis method based on the bond analysis was proposed to estimate cracking behavior due to drying shrinkage in RC wall, and the validity of the analysis method was verified from experimental study. However, because there is a shortcoming that calculation is complex, the simple estimation method is demanded. Accordingly, for the more simple estimation of the crack width and number of cracks of RC wall in the buildings, an improved and simple equation based on the bond analysis was proposed in this paper, and the calculation values were compared with the experimental values.