Model of 3 D flow field of crystallizer for beam blank was developed based on turbulent theory and characteristics of continuous casting. The model was applied to analyze flow field distributions with various nozzle and processing variables. It is found that the factors affecting the fluid flow of liquid steel in crystallizer are nozzle obliquity

immersing depth and drawing velocity. The results showed that it is beneficial to remove the inclusion at +15 ℃nozzle obliquity and to uniform flow field distribution at 0.9m/s drawing velocity. Proper nozzle depth is 200 mm. The model can be used to conduct off line analysis and to determine optimum variables as well as to lay the base of on line controlling model in continuous casting process.