<p>Plunge milling, which is recognized for its efficiency, has gradually been adopted for the roughing of integral impellers in recent years. However, several challenges persist, such as redundant tool paths, difficulties in managing the Sudden Increase of Radial Depth (SIRD), and excessive residual material in the adjusted tool path by plunge milling, which collectively constrain the efficiency of the plunge milling process. To address these challenges, this study proposes a five-axis plunge milling method with double-row slotting tailored for integral impellers. This method segments the machining area based on the width of the impeller runner and utilizes various tools with different diameters to enhance machining efficiency. The plunge milling path is optimized to facilitate efficient material removal while maintaining cutting stability, which addresses issues related to cutting overload and chip accumulation. In addition, an efficient method for SIRD identification and exclusion is proposed to minimize residual material. Simulation and practical machining results confirm that the proposed plunge milling method with double-row slotting significantly improves machining efficiency, which achieves enhancements of over 1.5 times compared with traditional methods.</p>