Abstract: A new method for electrochemical broaching of blind-hole internal gears using flat-jet electrolyte supply was proposed. To address the issue where accumulated electrolyte in blind holes affects jet velocity and machining accuracy, two cathode structures, namely the conventional flat-jet type and the liquid-extracting flat-jet type, were designed and comparatively investigated. Simulation analysis of the flow fields for both supply methods was conducted using Comsol Multiphysics. The results demonstrated that the liquid-extracting flat-jet type cathode effectively removes accumulated fluid from blind zones, thereby reducing flow resistance and enabling high-velocity jet processing. As a result, the machining rate was significantly increased, along with improved chip removal and process stability. Furthermore, the flow field uniformity was enhanced, leading to superior machining quality. Experimental results also confirmed its remarkable effectiveness in improving machining efficiency, accuracy, surface quality, and stability. This study provides a new approach and experimental basis for high-precision electrochemical machining of blind-hole components.