According to requirements of engine performance improvement and exhaust emission optimization, engine bench test data including 6 factors, i.e., rail pressure, fuel injection timing, air inlet volume, pre-injection fuel quantity, pre-injection timing and turbine inlet pressure, were collected in the world harmonized steady-state cycle（WHSC）. The central composite design was used in design of experiment（DoE）. A response surface model was established by regression analysis and the effects of 6 factors on fuel consumption and exhaust emissions were studied. Then the optimal solution was obtained by the model to obtain the fuel consumption and the emission value. The results proved that the response surface method（RSM）model was accurate. The model showed that when the turbine inlet pressure increased from 700 to 830 Pa（gauge pressure）, and the fuel consumption rate changed by 2.0%. The fuel consumption rate can be reduced by calibrating turbine inlet pressure.