In response to the challenge of measuring weak magnetic field, this paper introduces a novel detection method, combining source magnetic field superposition imaging. The approach involves injecting current into the grounding grid through multiple down conductors in periodic rotation, each inducing different flow directions within the grounding grid. This variation ensures effective stimulation of measurement magnetic fields across different areas of the grounding grid. Integrated with an ultra-wideband positioning system, the method enables real-time location tracking of array sensing coil measurements in both x and y directions on the surface level. The induced magnetic field is scanned and abnormal data interference is eliminated using morphological filtering and Canny edge detection. Simulation and experimental results show that the proposed method effectively improve the imaging quality of grounding grid topology. Moreover, the positioning accuracy error for grounding grid conductors remains below 3%, validating the effectiveness of the proposed method.