For the special casting environment of large round bloom mold with four‐hole nozzle, the reasonable choice of mold electromagnetic stirring (M‐EMS) location is of great significance to the quality control of bloom. In this study, the four‐hole nozzle arc continuous casting of φ600 mm‐large round bloom is taken as an example, a 3D mathematical model of liquid steel flow is built, and the solidification and heat transfer under M‐EMS is established. The optimum M‐EMS position was obtained as Z = 600 mm, which is enhanced flow rates, shell uniformity, and brittle interval width, and offers valuable insights for improving casting quality.