A detailed radiation model is proposed for radiative heat transfer calculations in laminar flames. The discrete transfer method is implemented in order to solve the equation of radiative transfer; the exponential wide band model is modified to avoid that thermal properties predicted by the original wide band model depend on the size of the numerical grid cells used in flame calculation. The overlapping correction among gases and mixture of soot and gases is considered. In addition, a phenomenological soot model for laminar premixed fiat flame is formulated. The applications of the detailed radiation model in CO/H-2/N-2-Air and H-2 - O-2 laminar counterflow diffusion flames and C2K4-Ar premixed burner stabilized flame are presented.