A mathematical model has been used to study the vaporization process of fuel film spread out on the combustion chamber surfaces in diesel engines, which consists of a system of differential equations of heating and vaporizing of the fuel film. The fuel film vaporization process is characterized as the coupling heat and mass transfer process. A corresponding calculation code is programmed using FORTRAN language. As an application example, the vaporization process of the fuel film on the combustion chamber surface in a 6E150C diesel engine is investigated quantitatively, and the effects of different parameters on the fuel film vaporization process are discussed. The experimental data support the calculated results.A drawing software is completed using C language, which can be combined with the above calculation software and receive the data from the calculated results. By means of the drawing software, the figures of the fuel film vaporization process can be displayed on the screen of computers and be plotted through printers, which makes the research of the fuel film vaporization process convenient.