A phenomenological multi- zone combustion model for DI Diesel engines is presented. The purpose of the study is to develop the capability of predicting engine combustion characteristics and soot emission with reasonable accuracy and economy. A new approach to zone division pattern and the major factors controlling in- zone combustion process is taken in the model for this purpose. Applications of this model are made to two DI Diesel engines and are validated by comparing the calculated and experimental results. A parametric study is then carried out.