 Abstract electric field reconstruction at interfaces is important for understanding how device performance is controlled. Scanning transmission electron microscopy, stem, and ab initio calculation were used to estimate the atomic scale and large scale potential reconstruction at the interface between a metallic oxide senior RU-03, SRO, thin film and an insulating DSCO-3, DSO substrate. The intensity and symmetry of the large-scale electrostatic reconstruction at the interface was probed using 4D stem, which discussed the center of mass shift for different angular ranges detection. Numerical simulations indicated that thermal diffuse-scattered TDS electrons could be sensitive to large-scale electric fields in experiments based on these diffused electrons near the interface confirmed that the electric field extended more into the insulating DSCO-3, DSO, side. The magnitude of the electrostatic drop at the interface estimated by the 4D stem experiment was in accordance with the ab initio values for a p-type reconstruction of the interface plane. Furthermore, an atomically resolved TDS potential asymmetry was observed in real space at the SRO slash DSO interface by 4D stem. This article was authored by Qingxian Jia and Alexander Gloder. We are article.tv, links in the description below.