A convection-effect-enhanced plate-type thermoelectric power generation module, of which the hot junction is directly heated by catalytic combustion of hydrocarbon fuel, was investigated. The convection effect with unburned mixture flows recovers heat conduction loss through the TEG element. A series of one-dimensional numerical analyses were made to examine the temperature field of the TEG module and to investigate the effect of various parameters on the convection effect. In addition, a model combustor using quartz plates was developed, mimicking the temperature fields of the SiGe TEG module. It is found that, with the aid of the convection effect, temperature differences over 700 °C between the hot/cold junctions can be achieved, while the unreacted fuel concentration is less than 10%.