The spray combustion process is varied intricately by the correlation of each the fuel components. It is effective to clarify the mechanism for not only understanding the phenomenon but also a concept for the new technology. Therefore, in this study, the vaporization behavior in the multi component fuel spray was analyzed with KTVA code extended for multi component system for clarifying the phenomenon and building up the basic theory of that The analysis indicated that the model proposed in this study was able to describe the distillation effect in the process of the multi component fuel spray. And then, it was indicated also that building up the model is necessary which can describe the liquid core and the large vortex structure in KTVA code and the diffusion of the species inside the droplet.