Sanmenxia Basin is located at the southeast of Fen-Wei Graben, between the Qinling tectonic belt and the intersection of the Neo-Cathaysian structural system. It is of great significance to investigate its tectonic framework for the oil and gas exploration in the basin. This paper characterizes the basin faults and divides its tectonic units using Bouguer gravity data and field observations. The results demonstrate that there are mainly three groups of faults in Sanmenxia Basin(near EW-trending, NE-trending and NW-trending), including 4 boundary faults, mainly in the form of fault belts, and 13 sub-basin faults and boundary faults. Most of these basin faults were formed in Pre-Cenozoic, and tended to be stable in Quaternary, with the characteristics of long extension and deep cutting. The Bouguer gravity anomaly in the western part of the basin is relatively high, the residual gravity field in the basin is distributed in a near-EW low-high-low strip trend from north to south, and there are multiple areas with different outliers. This phenomenon indicates that the Cenozoic sedimentary stratum is thick and there is a subsidence difference caused by the faults. According to the influences of the basement faults such as Zhongtiao Shannan Fault, Wendi-Gongqian Fault, Lingbao-Sanmenxia Fault and Sanmenxia-Kishi fault, Sanmenxia Basin can be divided into 3 secondary tectonic units and 9 tertiary tectonic units. From north to south, there lies the northern depression belt, the central low-uplift and the southern depression belt, showing an overall tectonic framework: belts in the north and south, and depressions alternating with uplifts.