Radiation heat transfer, apart from convection, is an important mode of heat transfer in diesel engines. In the paper a method for calculation of radiative heat flux distribution on the walls of the combustion chamber has been presented. Shape and volume of the burned zone as well of the combustion chamber are varying according to variation in a crank angle during the whole combustion process. Analysis of influence of degree of the burned zone transparency and value of the crank angle on radiative heat flux distribution has been presented and discussed. It allowed to find out that different parts of the combustion chamber may be differently thermally loaded.