Paleozoic Carboniferous-Permian strata occur sporadically in the eastern part of the Sanjiang Basin, their total organic carbon and other evaluation indexes of hydrocarbon source rocks are good, but their distribution in the basin has been unknown. In the background of the increasingly high cost of development and the urgent need of new oil and gas replacement area, the authors carried out oil and gas geological survey with gravity-magnetic-electric prospecting engineering in the Sanjiang Basin and established a comprehensive inversion profile through qualitative analysis, integrated information inversion and imaging for the purpose of identifying the developmental characteristics of the Carboniferous-Permian strata in the Sanjiang Basin,. The physical properties of the strata in the study area were systematically studied and summarized, and the distribution characteristics of the Carboniferous-Permian strata was preliminarily characterized by the use of magnetotelluric sounding inversion resistivity for the low-resistance marker layer. Then, the distribution characteristics of the Carboniferous-Permian mudstone were explored by the residual treatment of the two-dimensional inversion resistivity section.