According to the exploration results of two magnetotelluric sounding profiles in central Guangxi area, the authors have studied the geological structure of central Guangxi depression and its surrounding areas. Central Guangxi depression is divided into four sub-units, i.e., northern slope, western slope, central depression and eastern slope. The depression was developed on the basis of lower Paleozoic epimetamorphic rock series, and the average thickness of Devonian strata reached 4 000 m. The electrical characteristics show that the Middle-Lower Devonian strata constitute the main horizon of the biogenic reef, and the electricity is characterized by relatively stable low resistance. Two-dimensional inversion of the section has revealed an electrical anomalous body with the character of "high in low", which is inferred to be a reef. Brachyanticlines are well developed in the central depression, and hence the central depression and its surrounding areas are considered to be favorable areas for oil and gas exploration.