Abstract: Based on actual dimensions of the copper plate and the back plate, a physical model was constructed. Meanwhile, a three-dimensional heat transfer and cooling water flow mathematical model of the copper plate of the mold was established. Coupled numerical simulations were conducted on the heat transfer and cooling water flow of the narrow-face copper plates of the right-angle and chamfered mold. The results show that when the water volume is 510 L/min, the macroscopic average water velocity of the right-angle and chamfered mold are 8.8 m/s and 7.4 m/s, respectively. The water velocity in the circular holes near the corner of the copper plate of the chamfered mold is only 4.8 m/s to 5.1 m/s, while the water velocity in the water gap near the edge of the right-angle mold reaches more than 8 m/s. In the meniscus area, the corner temperatures of the narrow copper plates of the right-angle and chamfered molds reached 677 K and 763 K respectively. When the diameter of the circular hole at the water inlet of the copper plate in the chamfered area is increased from 10 mm to 14 mm and the water volume on the narrow side of the mold is increased to 540 L/min, the water velocity at the edge circular hole can be raised to 6 m/s, which is conducive to enhancing the cooling intensity at the corner of the chamfered mold.