Abstract: In order to solve the problems of low dephosphorization rate in the early stage of steelmaking，high oxygen content at the end-point of blowing，low tapping temperature and short life of oxygen lance in 260 t converter in Hanbao Steelwork, Handan Iron and Steel Company，a series of investigations were carried out during the steelmaking process through sampling，temperature measurement，recording and analyzing key operating parameters. According to the investigation results，the parameters of oxygen lance nozzle and the curve of lance position during blowing were optimized，and the maintenance of bottom tuyeres was strengthened. The pressure loss in the oxygen supply pipeline and the characteristics of the jet flow field of the nozzle were measured，and the water model test of the effect of the jet on the converter bath was carried out.Through the above process optimization measures，the dephosphorization result of the converter has been improved，the end-point carbon and oxygen content product in the molten steel has been reduced to 0.002 39，the average tapping temperature has reached 1645℃，and the average lance life has been doubled to 320 heats. The consumption of other materials such as ferrous charge and lime has also been improved significantly，the amount of scrap has been increased and the economic benefit achieved has reached 40.02 yuan/t. The converter steelmaking process reached the technical level required to produce low-carbon high-quality deep drawing steel.

Key words: converter steelmaking, the ratio of dephosphorization, oxygen content, end-point temperature, process optimozation