Combustion method is a simple method to synthesize carbon nanotubes(CNTs), which employs flames of carbon-contained reactant to synthesize CNTs. It has been proved that combustion method is an effective method to synthesize carbon nanotubes and carbon nanofibers. In this paper, we reported the synthesis of CNTs by using ethanol catalytic combustion with an additive of thiophene, which employed ethanol as carbon source and fuel, nitrate as catalyst precursor, stainless steel as substrate, and thiophene as accelerant. Compared with previous reports on the synthesis of CNTs by ethanol catalytic combustion, great yield of CNTs were obtained with adding thiophene in ethanol. The reproducibility of the synthesis of CNTs in the case of adding thiophene in ethanol was greatly improved.