Value of hydrogen as an energy is growing because new applications for fuel cells to generate power will be commercialized in the future. Autothermal reforming (ATR) is the preferred choice for vehicle applications of higher hydrocarbons owing to its start up time. Moreover the ATR product gas, containing mainly H2, CO, CO2, CH4 and H2O can be utilized in solid oxide fuel cells (SOFC), albeit the selectivity to hydrogen is lower in ATR than in Steam Reforming (SR). In addition, ATR of diesel, at least, is thermally more stable than SR. But ATR of hydrocarbon mixture like diesel and liquid fuels has not been studied sufficiently. Noble-metal-based catalysts have been reported to be more effective at preventing coke deposition, since they do not dissolve carbon. However Group VII metals, such as Rh, Ru, Pt and Pd were much more expensive than Ni. Also, the Ni catalyst are more prone to deactivation due to sulfur poisoning and coke formation. In this study, the dodecane (C12H26), hexadecane (C16H34) and 1-methylnaphthalene (C11H10) were chosen to surrogate diesel fuel and aromatic hydrocarbon, respectively. We examined in detail Ni-Al based catalysts in the autothermal reforming reaction. The Ni-Al based catalysts were prepared by polymer modified incipient method and tested at S/C=1.17, O2/C=0.24, 750 ℃ and GHSV = 12,000 hr-1. The commercial catalyst RhA5-CL indicated the excellent catalytic activity and H2 yield at DH (dodecane, hexadecane mixtures) and DHMN (dodecane, hexadecane and 1-methylnaphthalene mixtures) conditions. But NA10-PM catalysts was deactivated with reaction time at DHMN condition. In XRD and XPS patterns founded that the Ni metal structure was disappeared in catalyst surface. In other words, carbon deposition produced by autothermal reforming reaction was covered Ni metal active site. It was shown that SEM-EDX images. Ring-shaped carbon deposition was spread on catalyst surface. Specially, this carbon deposition was covered inside of pores. It means that carbon deposition by autothermal reforming was caused catalytic deactivation. So, we founded that relationship carbon deposition and reaction product. The amount of carbon deposit with increasing can be seen that the amount of a certain product increases. That product was indicated ethylene (C2H4). Actually, ethylene has been reported in the literature that affect the carbon deposition. To reduce the carbon deposition, we increased the active sites of Ni metal. Catalytic activity of NA50-PM catalyst was maintained a period of time but it was still reduced. So, we tested that low content of noble metal Rh added in NA50-PM to have carbon resistance. Rh2NA50-PM was excellent catalytic activity and H2 yield compared to RhA5-CL. In addition, the amount of ethylene product was reduced more than half and the amount of carbon deposition was reduced, significantly. It was concluded that Ni-Al based catalysts made by polymer modified incipient method were shown excellent catalytic activation for a period of time and adding a small amount of noble metal Rh in NA50-PM that Rh2NA50-PM catalyst had seen similar catalytic activity.