In order to study the phenomen occurring in converter during steelmaking process,a three dimensional mathematical model of an 150 t six hole oxygen converter was set up using the commercial software Fluent 16.0. The top blowing process was considered in the current calculation. The effects of the different ambient temperatures on the velocity of the oxygen jet, slag distribution, surface velocity liquid steel, and distribution of wall shear stress were investigated. The results show that, with the increase of temperature, the velocity of the oxygen jet increases and the time of blowing open slag layer cuts down. Meanwhile, the biggest velocity at the surface of the liquid steel is greater than 10 m/s, and the level fluctuation of the liquid steel increases. With the increase of temperature, the wall shear stress rises up and the wall shear stress near the interface of the gas phaseslag phasesteel liquid phase is the largest.