A multi-zone mathematical model of film-space atomization combustion in direct injection diesel engines is presented, which consists of a submodel of evaporation and combustion of the fuel film sprayed on the combustion chamber wall and a submodel of atomization combustion of the fuel sprayed in combustion chamber space. The fuel film sprayed on the combustion chamber wall is divided into many subzones and the fuel sprayed in the combustion chamber space is considered as one subzone. The submodels are combined through the conservation of the energy and mass in the full film-space atomization combustion system, and an overall system of differential equations are given. The initial and boundary conditions are resulted from the experiments on diesel engines. By means of the model, the film-space atomization combustion processes in 6E150 diesel engine are investigated quantitatively. The comparison between the calculated results of the model and the experimental data is satisfactory.