Abstract: This paper systematically collected and compiled Bouguer gravity anomaly (BGA) data from the Caspian Sea region, produced a BGA map of the area, and subsequently explored the characteristics of fault structures in the Caspian Sea region based on this data. Utilizing edge detection technology for potential fields, corresponding edge recognition information was acquired. Detailed analysis of the Bouguer and residual gravity anomalies, based on existing geological and geophysical research, allowed for the determination of the regional fault structure framework and the classification of tectonic units in the Caspian Sea area. The results show that the gravity anomalies in the Caspian Sea region exhibit distinct zonation. Bounded by the Nebitdag–Makhachkala–Kizlyar line, the northeastern part of the boundary shows relatively minor macroscopic gravity variations, whereas the western and southern parts of the boundary exhibit more intense changes in the gravity field. On the basis of the gravity anomaly features manifested in the study area, eight first-order faults (F1–F8) were identified in the Caspian Sea region. Exhibiting substantial scale and continuity, these faults exert a fundamental control on the tectonic framework of the Caspian Sea region. The region comprises five first-order tectonic units: the Russian Platform, the Ural Fold System, the South Turan Fold System, the Scythian Fold System, and the Tethyan Fold System. This work provides provides geological and geophysical support for petroleum exploration in the Caspian Sea region.