Unveiling the origin of local charge transfer is crucial for advancing electronic devices such as ferroelectric and memristive memories and perovskite solar cells. Exploring charge transfer mechanisms requires sensitive probing of local charge transfer, as electric charges in many materials arise from multiple mechanisms. However, the limited sensitivity of current techniques makes it challenging to unveil the origins of such nanoscale charge behavior. To address this challenge, we propose highly sensitive accumulative charge transfer spectroscopy (ACTS) for probing dynamic charge behaviors at the nanoscale in oxides and hybrid halides, including Pb(Zr