Abstract: Some experience of the process and operation on refining ultralow carbon ultra low sulfur steel were introduced. Through the comparison of low sulfur and ultra low sulfur steel production, control routing of sulfur content was obtained，and process capability index of w(S)≤0.003 5 % in slab was increased from 0.85 to 1.13. By pretreatment of hot metal, material quality control，production plan optimization，desulfuration in RH, heats produced by ordinary process, the sulfur mass fraction within 0.003 % proportion can reach more than 90 % in slab. Heats produced by desulfuration process, the sulfur content within 0.002 % proportion can reach 100 % in slab. The control of sulfur element ability received a significant improvement.

Key words: ultra low sulfur steel, desulfuration, control of sulfur content