The present paper deals with the morphological characteristics of soil structure and their relations to shringkage and swelling. Four paddy soils used in the study were collected from Taihu lake region. The content of clay in the soils ranged from 20-40%. Plough layer and plowpan of clayey paddy soil are characterized by puddling and compactness. Weathering may advance the formation of structural pores of the soil. There are internal relations between behaviors of soil shrinkage and swelling and regime of soil structure. There are three shrinkage stages of a clyey soil clod in the drying process, i. e., structural shrin-kage, normal shringkage and residual shrinkage. The ratios of tre change of soil volume to volume of water lost from soil in the three stages are <1,1 and <1 respectively. When structure of clod is destroyed, the structural shrinkage disappears and normal shrinkage develops. Therefore the characteristics of soil shrinkage can reflect the regime of soil structure.