Abstract: In numerical calculation of steady combustion flow field,the governing dif-ferential equations can be discretized with finite difference schemes and solved with iterative method. But their convergence solution can be attained only with good estimates of initial conditions.Instead of empirical estimate of the initial conditions,an approach to specify the initial conditions is presented,based on the mathematical simulation of the forced ignition. In the result, the initial conditions can be determined computationally by setting a catalytic boundary in the combustion zone.