To study the dry shrinkage of cement stabilized soil (CSS) and its size effect, two types of clay from the engineering field of a key water-control project in Mengcheng were tested for indoor dry shrinkage performance. The shrinkage of CSS of different cement content and under various curing time was measured and the size effect on shrinkage was compared. The results show that, the shrinkage of CSS increases with extension of drying time, and tends to be stable after 14 days. As the content of cement increases, dry shrinkage decreases. The extension of curing time is beneficial to dry shrinkage performance with limited effects. There is a positive correlation between dry shrinkage and mass loss rate. The size of specimen has little effect on dry shrinkage with non-significant size effect. 