Abstract: Reference 1 takes no account of the variation of compression of soil with depth in the bottom aquifer (B.A) in analysis of the interaction between soil and shaft wall during deep soil dewatering. Aiming at this point, a new ideal elasto-plastic model which is elastic in the shallow and bottom parts and plastic in the deep has been established. The new formulae to calculate the additional vertical displacement, strain and stress of shaft lining are obtained. Finally presented is an example to show the feasibility of the new model.