Abstract: Analysis for the effect of 3-D seepage and sand drain group on consolidation of foundation is performedwith Terzaghi-Rendulic's 3-D consolidation equation in this paper. Analytical solution which takes into account theeffect of the interaction between sand drains, 3-D seepage and well resistance, and satisfies the drainage condition onthe top and bottom boundary of the soil as well as the flow continuous and well resistance conditions of each sanddrain is presented. The effect of 3-D seepage and sand drain group on the pore pressure dissipation and foundationconsolidation is also discussed through numerical computation.