Preliminary determination of structures and stratigraphy are achieved by two-dimensional inversion of successive magnetotelluric sounding. Based on overall analysis of stratigraphical and petrophysical parameters defined by regionally physical properties, a preliminary forward model of geology and geophysics has been created. Combined gravity and magnetoelectric inversion commenced by geological, drilling and seismic data constantly revises the geological-geophysical model and the successive two-dimensional inversion result from magnetotelluric sounding, bringing the gravity-magnetic forward data and measured data to the most optimum fitting degree. Combined gravity and magnetoelectric inversion used for interpretation of tectonics and stratigraphy of the Yingen-Ejinaqi basin can effectively solve the problems derived from a single method and accurately indentify horizons of stratigraphy, thus greatly improving the accuracy of quantitative interpretation.