Abstract: The magnetotelluric sounding exploration for the Mesozoic and Paleozoic formations has been carried out in the recent years in the north part of Jiangsu province. The stratum columnar section consists of six electrical layers, among which three layers are low-resistance ones and three high-resistance. Comprehensive geologic interpretation is performed on data after field preprocessing, cleaning-up of static displacement, and 2D inversion. Based on interpretation of magnetotelluric sounding data, we infer the classification of structures and the distribution of residual marine strata in Jianghu Buildup and the north in the north part of Jiangsu province. Results show the marine middle and upper Paleozoic residual strata mainly locate in the east part of the survey area, and the lower Paleozoic residual strata locate only in the west part. The residual marine strata are controlled by the reverse thrust of NE direction that was developed from the south end of Funing sag in the middle of Indo-chinese and Yanshanian epoch and a series of normal faults of NW direction.