To address the issue of the increasing trend of temperature in the key area of the chip rise caused by increasing power density in insulated‑gate bipolar transistor （IGBT） modules，a fluid-solid coupling model of the IGBT module and water‑cooling plate was established，and an optimized design method for the water‑cooling plate of the IGBT module was proposed.The effectiveness of the method was verified through finite element simulation and experiments.Based on the dimensions and heat dissipation power characteristics of the IGBT module，three water‑cooling plates with different heat dissipation areas （122 mm×61 mm×20 mm，122 mm×122 mm×20 mm，122 mm×183 mm×20 mm） were simulated，analyzed，and optimized to systematically evaluate the influence of heat dissipation area on cooling efficiency.After determining the optimal size，straight ribs were welded inside the flow channel，and an orthogonal experimental method was employed to derive the optimal structural parameters（flow channel depth，rib height，and rib thickness）.The results show that when the flow channel depth is 9 mm，the rib height is 5 mm，and the rib thickness is 1.5 mm，the optimized water‑cooling plate reduces the maximum temperature of the IGBT by 7.1 ℃，significantly improving thermal performance.Comparative experiments under different power losses and inlet water temperatures verifies the variation patterns of the maximum temperature on the chip and substrate surfaces，confirming the effectiveness of the proposed optimization scheme.This study provides a new solution for the thermal design of IGBT modules，which is of great significance for promoting their applications in renewable energy generation，smart grids，and high‑power electronic systems.