The software for the static control of the LD steelmaking process has been presented, based on a detailed physico-chemical model. The software is able to calculate the optimum charge composition and the amount of oxygen to be used to achieve target temperature and C-content of steel, during blow. The software can be used also in training of steelmakers, as it can simulate the LD-process. The influence of different parameters on the steel temperature has been obtained in this paper. Our data are confirmed by empirical thumb rules established empirically in the plant. However, when several parameters are changed at the same time, the thumb rules fail, as the process is not linear. In this case the software should be used to achieve optimum process parameters.