A mathematical model for supersonic jet oxygen lance with axial calculated length 2 200 mm and diametrical calculated length 800 mm is established by using GAMBIT and the numerical simulation study on characteristics of the supersonic jet oxygen lance has been carried out by using FLUENT software. The supersonic jet characteristics of single hole oxygen lance and the effect of operating pressure (0. 6 〜1. 0 MPa) and ambient temperature (298 〜1 873 K) on flowing characteristics are analyzed. Results show that the effect of stagnating pressure at entrance within designing pressure ±25% on jet flow axial weakening and diametrical expanding is not obvious； the relation between stagnating pressure and length of flow jet supersonic region presents quadratic form curve change； with enhancing ambient temperature the jet flow axial weakening is slow and the length of core region increases

the length of supersonic jet region is linear with the ambient temperature

and the effect of ambient temperature on diametrical jet flow is minor.