Abstract: Based on the analysis of the problems existing in combusting diesel fuel currently, the orthogonal experiments were made on an S195 type diesel engine to determine the relationship between three working parameters, i.e. fuel-delivering angle, injection pressure, and diesel fuel temperature and specific fuel consumption under 6 different working conditions of the engine when three different kinds of diesel fuels, which are the mixtures of the No.0 diesel fuel with the 5%, 10% or 15% No.20 diesel fuel, respectively, were used as the diesel fuel. By means of SAS (Statistical Analysis System), the optimum working parameters and the sequence of factors, according to their influence on the specific fuel consumption of engine under different working conditions, were selected. Laboratory experiment and practical application tests show that diesel engine cannot only function normally, but also its power characteristics was enhanced and the use cost was reduced when the mixtures were used.