Finite element method based on Biot consolidation equation taking into account the interaction between soil skeleton and pore fluid is always used to analyze the consolidation of saturated soft foundation with undrained-incompressible limit. Because of restriction of Babuska-Brezzi inf-sup condition

conventional FEM based on equal interpolation orders u-p formulation will give a spurious oscillation result for pore pressure. Based on displacement-pressure linear equal interpolation

a new method in which the number of the independent degree of freedom of displacement is higher than that of pore pressure

is proposed. With suggested double-mesh interpolation method

the Babuska-Brezzi stability condition will be satisfied; and it is possible to use equal interpolation orders u-p formulation. Several examples are presented to verify the suggested method.