Sodium/potassium-ion storage devices have ushered in a turning point in development, becoming a new trend in energy storage devices after lithium-ion batteries (LIBs). Carbonaceous material, as a very promising negative electrode for sodium- and potassium-ion storage electrodes, has been widely studied and applied. Clarifying the energy storage mechanism of carbonaceous materials to guide the controllable synthesis of carbon is a key issue in carbon science. Electrochemical behavior is usually the most intuitive representation of the understanding of the mechanism and structural changes of material energy storage. Obtaining the regularity information on carbonaceous materials from electrochemical characteristic curves is a valuable consideration. In order to comprehensively and profoundly understand the structural properties of carbonaceous materials and the electrochemical reaction regularity characteristics brought about by carbon structure changes, this review starts with modeling electrochemical curves, systematically summarizes the structural characteristics of carbonaceous materials corresponding to each model and analyzes the transformation regulation among models, providing comprehensive insights and guidance for mastering the sodium/potassium-ion storage characteristics of carbonaceous materials. The preparation, modification, and large-scale application of carbonaceous materials have been systematically summarized. In addition, our perspectives on the future development of carbonaceous materials for energy storage applications are provided.