<p>Based on the original technique of stratifying and separating potential fields, this paper introduces an improved interpolation cutting algorithm based on inverse distance weighting technology. The algorithm allows for the layer-by-layer separation of potential fields. The effectiveness of the improved algorithm in separating potential fields is demonstrated through the separation of potential fields, analysis of anti-noise performance, and depth analysis of the gravity anomaly field obtained from an ideal model. In comparison to the Bouguer gravity anomaly distribution map, the local gravity anomaly field at different depths is able to effectively suppress the influence of the regional background field, and providing a clearer representation of the structural characteristics at specific depths. The improved interpolation cutting algorithm is applied to separate the potential field of the Bouguer gravity anomaly in the southern section of the Tan-Lu fault zone and the surrounding area. The research findings indicate that the distribution pattern of local gravity anomaly in the study area has a stronger correlation with the strike of faults compared to the Bouguer gravity anomaly. Additionally, the density of the shallow crust in the study area is relatively homogeneous, while the density of the middle and lower crust is less homogeneous. The southern segment of the Tan-Lu fault zone exhibits distinct segmentation characteristics, as it is intersected by the Huai Y–Xiang SK fault. Furthermore, the cutting depth in the southern part of the fault is deeper.</p>