Abstract: Numerical simulation of the working process for the gasoline engine 462PFI was performed with the WAVE code. The results showed that the prediction accorded well with the measurements. In order to satisfy combined simulation and optimization for the engine, the multi-objective and multi-parameter nonlinear restriction programming was performed using the Matlab code that transfered the import parameters such as the structural, injection, valve timing, combustion timing and other parameters to the simulation model. Under conditions of weights given it can be aimed to give the best matching of parameters so as to make the engine provide the highest power, the best possible fuel consumption, and superior characters of emissions.