The dynamic interfacial tensions between crude oil and surfactant solution were measured. The data showed that some surfactants dramatically reduced the interfacial tension as well as the tension of oil/water interface to ultralow (under 10(-2) mN/m) at a very low surfactant concentration. Moreover, different aromatic rings showed different effects on the reduction of the oil/water interfacial tension. Methylphenyl-SAM and Dimethylphenyl-SAM with proper aromatic rings on their arylalkyl chains exhibited better interfacial behaviors than Phenyl-SAM with a relative small aromatic ring (phenyl) and Naphthyl-SAM and alpha-Methylnaphthyl-SAM with larger ones (naphthyl and alpha-methylnaphthyl) on their arylalkyl chains. The authors' findings demonstrated that the above-mentioned solutions could lower the oil/water interfacial tension to ultralow over a wide surfactant concentration and alkalinity ranges.