Abstract: A new approximate solution to thickness reduction ofplastic bending sheet is presented by considering the characteristics ofdeformation and stress distribution. The proposed method is based on theincremental theory, and volume invariance and planar cross-section areassumed. As a calculation example, the sheet reduction ratio and the distancefrom the neutral plane to inner boundary are calculated and compared withpublished data. A fairly good agreement is obtained between the calculatedresults and the experimental data.