Combustion mode of Al-TiO₂-C-Ti-Fe system was studied by means of computer combined with rapid image collecting. The results show that the Al-TiO₂-C-Ti system presents typical plane combustion mode. The Al-TiO₂-C-Ti-20wt%Fe system exhibits multiple-point undulation combustion mode because of decrease of combustion temperature, the melting of Al and the heat exchange. The undulation degree weakens with the increasing of Fe content. However, an unusual phenomenon was first found that the combustion wave steadily propagated again as plane combustion mode with further increasing of Fe content, i-e. the decreasing of adiabatic temperature (such as Al-TiO₂-C-Ti-50wt%Fe system). The possible cause is that the combustion wave with high temperature points is unlikely to be prior to propagate due to the low adiabatic temperature (approaching to 1800K) and the low undulation of temperature at combustion front.