At present, the taper values of high-efficiency crystallizer copper tubes used by various steel mills are generally 0.6-0.9. When the low-carbon steel and low-alloy steel are pulled, the taper value is taken as the middle and lower limit, and the drawn medium carbon steel and high carbon steel are the upper limit of the taper value. In order to ensure that the inner cavity of the copper tube is consistent with the cooling shrinkage of the slab throughout the length of the crystallizer, the inner cavity of the crystallizer copper tube should be a parabolic continuous taper. When casting low carbon steel and low alloy steel, the apex of the parabola should be designed at the lower end of the copper tube. At the same time, the taper distribution of the high-efficiency crystallizer should also match the other process parameters in the drawn steel.