Nine pure sodium phenylalkane sulphonates, namely, 3-phenyltetradecane, 5-pheyltetradecane, 7-phenyltetrdecane, 3-phenylhexadecane, 5-phenylhexadecane, 7-phenylhexadecane, 1-phenyldode-cane, 1-phenyltetrdecane and 1-phenylhexadecane sodium sulphonates, were prepared and their capabilities for lowering dynamic interfacial tension (D-IFT), were evaluated in n-octane/NaOH aqueous systems. The effects of surfactant structure and the concentration of added NaOH on the tension behaviour of these anionic surfactant systems, were studied. Tension behaviour of surfactant are considered the backbone for evaluating and designing practical formulations used for surfactant flooding systems.