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When operating under low flow conditions, the hydraulic performance will be deteriorated due to the low inlet speed and the backflow near the wall, which will produce serious unit vibration and threaten the safe and stable operation of the pump station. The groove flow control technology for axial-flow pump is an effective method for enhancing its hydraulic performance. However, the influence of its structural parameters on hydraulic performance remains unclear. Numerical simulations were utilized to modify the groove structure by changing the important geometric parameters. The impact of single-factor and multi-factor variables of groove structure on the hydraulic performance in deep stall conditions was investigated, with optimization of groove structure parameters conducted by using the response surface methodology. Results indicated that among three parameters of groove tail distance, groove depth, and groove width, the most pronounced influence on both hydraulic performance and internal flow field of axial-flow pumps was exerted by the groove tail distance. The optimal combination for key geometric parameters of axial-flow pump grooves was as follows: h (groove depth) equaled 0.022 times impeller diameter;W (groove width) equaled 0.088 times impeller diameter;L2 (groove tail distance) equaled 0.106 times impeller diameter. These research findings provided valuable support for groove flow control technology in designing and operating axial-flow pump device.