The present invention provides a method for controlling the surface quality of an ultra-low carbon steel slab, the method comprising the steps of: measuring the phosphorus (P) concentration, sulfur (S) concentration and superheating degree of a molten steel which is introduced into a mould in a continuous casting process for producing the ultra-low carbon steel slab, the width of the mould, and the casting speed of the slab; and calculating the depth of a hook which is formed when the molten steel is solidified into the slab, based on the measured width of the mould, the measured phosphorus (P) concentration, sulfur (S) concentration and superheating degree of the molten steel, and the measured casting speed of the slab.