A lot of drosses appear on surface of molten zinc in the process of continuous hot dip galvanizing. The drosses,if not cleared in time,adhere to the surface of hot galvanized sheet and lead to surface defect. The production of zinc dross is closely related to the physical fields of molten zinc and dross remove can change of the physical fields,so it is necessary to carry out systematic research on the physical fields. Through the standard k-ε turbulence model and the geometric model of galvanizing pot and molten zinc,the author finds out the distribution regularities of the physical fields（ such as speed,temperature and concentration field） and the laws of these physical quantities changing with time,and determines the distribution characteristics of the vortex. The theoretical calculations can be used to predict the distribution regularity of zinc dross and the danger zone of the dross removing operation,provide important theoretical basis for the design of dross removing robot,and ensure the quality of zinc coating and improve the efficiency of dross removing.