Thermal analysis has been conducted numerically on a film cooled ramjet combustor with combining experimental data. The film cooling effectiveness and heat transfer coefficient on the exposed combustor wall were taken experimentally in a cold flow test to obtain the thermal boundary conditions. Distributions of temperature and thermal stresses on the combustor liner were calculated by using the boundary conditions from experimental data and a commercial code, ANSYS. The high thermal stress appears after the stabilizer wall. That is also the region attached by combustion flame. Thermal fracture will occur on the region of high thermal stress due to high temperature difference. The present results of temperature and stress distributions provide a guide line for thermal design in a film cooled ramjet combustor.