The drainage controlling ground treatment method(DCM) is a new ground treatment method which accelerates the pore pressure dissipation to accelerate settlement as fast as possible during construction period and decelerates ground post-construction settlement to control the post-construction settlement furthest by confining the excess pore pressure dissipation of the ground during the operation period. Finite element method technique like hexahedron pore fluid element and linear prefabricated vertical drainage element is adopted. The relationship between ground post-construction settlement and the depth of anti-seepage curtain and prefabricated vertical drainage is revealed. The regularities of the distribution of the ground post-construction settlement and the excess pore pressure with time and space are also revealed. Conclusion is drawn as follows: The DCM has the special effect of achieving 0 post-construction settlement with relative low engineering costs and relative short duration; high performance price ratio can be pursued by setting relative shallow anti-seepage curtain and relative deep prefabricated vertical drainage; decrease of the effective stress during operation caused by increase of the excess pore pressure in the sealed scope is the main reason of DCM decreasing the post-construction settlement.