The dynamic interfacial tension between Daqing oil and alkanolamide surfactant system(Cn(m+m)) was measured and the effect of carbon chain length(n) and hydrophilic groups(m) was studied.Experiment results showed that the interfacial tension of alkanolamide surfactant with the same n increased gradually when m changed from 1 to 3.When the number of hydrophilic groups was of 1,the interfacial tension of alkanolamide surfactant did not decrease with increasing carbon numbers.While m was of 2 or 3,the interfacial tension decreased with increasing n.The interfacial activities of different series alkanolamide surfactants were deeply researched by organic concept map.And the ratio of hydrophilicity to lipophilicity(I/O value) of the surfactants was calculated.Based on the organic concept diagram theory,the more access to zero the |I/O-1| value,the better interfacial activities of alkanolamide surfactants.The |I/O-1| value of C16(1+1),C14(1+1),C18(1+1),C12(1+1) was of 0.03,0.09,0.13,0.25,respectively.That of C16(1+1) was closest to zero,and that of C14(1+1),C18(1+1) and C12(1+1) increased by sequence.The values of calculation were consistent with that of the determination.Therefore,under the condition of the same n,the |I/O-1| value of surfactants in the organic concept diagram would deviate away zero with increasing m,which reflected the worse interfacial activities of the surfactants.