Abstract: Taken the northern Ordos basin as example,the research focuses on the evolution of palaeoflow field with 3D numerical modeling to revert the strata thickness,geologic and hydrogeologic conditions in different era of late palaeozoic,First,the palaeozoic stratum thickness is different era is reverted according to the compression equation,the geologic and hydrogeologic conditions in different era are reverted,too.Second,based on the conceptual model of palaeohydrogeology,the mathematics model describing the palaeoflow and accounting for several factors,such as compression,hydrocarbon yield and dehydration of clay mineral,is deduced.The finite difference approach is used to solve the mathematics model.The result indicate that the evolvement of palacoflow field can be perfectly demonstrated by using three dimensional modeling of palaeoflow in northern Ordos basin,and the favorable arca,in which the oil and gas is probably stored,can be ascertained.