The present study is mainly motivated to investigate the vaporization. autoignition and combustion processes in high-pressure engine conditions. The high-pressure vaporization model is utilized to realistically simulate the spray dynamics and vaporization characteristics in high-pressure and high-temperature environment. The interaction between chemistry and turbulence is treated by employing the Representative Interactive Flamelet (RIF) Model. The detailed chemistry of 114 elementary steps and 44 chemical species is adopted for the n-heptane/air reaction. In order to account for the spatial inhomogeneity of the scalar dissipation rate, the multiple RIFs are introduced. Special emphasis is given to vaporization effects on the mixture fraction fluctuations and the pdf model. Numerical results indicate that the RIF approach, together with the high-pressure vaporization model, successfully predicts the essential features of ignition and spray combustion processes.