With the increasing demands for energy utilization and storage, the secondary lithium batteries with high energy-density and high safety performance are being continuously developed and improved. An in-depth understanding of the electrochemical process and corresponding micro-mechanism at the electrode/electrolyte interface of lithium batteries during charging and discharging is beneficial to open new avenues of guiding the optimal design of battery materials. In situ electrochemical atomic force microscopy (AFM) combines high-resolution surface-imaging of AFM with electrochemical characterizations, unraveling the direct visualization and dynamic evolution of the electrode/electrolyte interface in a working battery at nanoscale. This article reviews the latest research progress of in situ electrochemical AFM investigations into the electrode processes of lithium batteries, including the interfacial reaction process of the conversion-type cathode, the dynamic evolution of the solid electrolyte interphase film at the electrode/electrolyte interface, and the structural evolution in solid-state lithium batteries.