Abstract: By analysing and disposing the experimental data from Shanghai NO. 5 I&S Works, comparing these data with the results undertaken by some investigators, the equilibrium conditions of C-O, Cr-O, C-Cr during stainless steel making in STB combined-blown converter are approached. The results show that the C-Cr equilibrium relation is different from Hilty's equation which is suitable for the stainless steel making in electrical furnace. Therefore, it is not very accurate to measure the C-Cr equilibrium conditions in STB combined-blown converter.