Abstract: In order to further improve the stability of end-point control of converter，the main factors affected the carbon-oxygen equilibrium of converter were analyzed from the point of view of improving kinetics，and the control technology of reducing the carbon-oxygen equilibrium of converter was determined by industrial test. The results showed that，the mixing time of molten steel was the shortest when the number of tuyereswas 4 and the layout of tuyereswas 0.50D on the circumference of the converter bottom；the proportion of particles size of magnesia 0—1mm in the fetting materialwas 20%，the high temperature flexural strength was increased from 4.2MPa to 5.3MPa，and the permeability was increased by 227%. The oxygen mass fraction at the end of the converter further decreasedfrom 482×10-6 to 425×10-6，reduced by 57×10-6by employingthe quick change technology of the tuyere for converter. Through the above measures，the visualization of the tuyerewas realizes in the whole campaign life，and the carbon-oxygen equilibrium wasreduced from 0.00238 to 0.00178 in the whole campaign life.

Key words: combined converter, carbon-oxygen equilibrium, fetting material for converter, quickchange technology of tuyere