Using limestone to displace some lime in converter can decrease the production costs of steelmaking and reduce the emission of carbon dioxide.The industrial tests and thermodynamic analysis were carried out to investigate the effect of limestone substitution ratios (18%,19%,20%,25%,28%,29%,39% and 41%) on the dephosphorization efficiency,converter gas composition and oxygen lance position.The results show that better dephosphorization efficiency can be achieved when the limestone substitution ratio is 25%,and the end point phosphorous content is 0.016%,which is reduced by 47% compared with the original process of 0.030%.Meanwhile,the moment of recovering the converter gas is one to two minutes earlier than before,and the amount of recovered gas increases.Furthermore,the more limestone is added,the earlier recovery time is.The results also show that the oxygen lance control position should be raised from 1.7 m to 1.8 m when using limestone to displace some lime in steelmaking.