Abstract: Aiming to study the effects of vitiation species on combustion characteristics, comparative tests are conducted in a kerosene fueled supersonic combustor using an electrical heating facility and a methane combustion heating facility. For both clean and vitiated air, the total pressure and total temperature of the combustor entrance in every test are fixed at 820 kPa and 840K, and the Mach number is about 2.0. In comparative tests, combustion luminosities images are obtained using a high speed camera. Based on these images, the kerosene combustion flame-spreading angles are acquired. Experimental results indicate that, compared with the clean air, the combustor peak wall pressure decreases by 3.1%~6.9% with the methane combustion heated airflow, and the flame spreading angle decreases by 7.1%~12.4%.