Abstract: The numerical and physical models of the crystallizer for three-dimensional flow field analysis were established based on the process conditions of 180 mm×505 mm slab continuous casting. The effects of immersion nozzle dip angle, immersion depth and pulling speed on the flow field of the crystallizer were analyzed by using Fluent software. The results show that when the casting speed is 1.1-1.3m/min, the immersion nozzle with an angle of 15° can meet the requirements of liquid surface stability; when the casting speed is increased to 1.3-1.5m/min, the liquid level slag can be suppressed by using the nozzle with dip angle of 20° and the immersion depth of 130-150mm.