A series of novel dialkyl disulfonate Gemini surfactants (C n -GSBS, n = 8, 12, 14, 16, n is the carbon number of the hydrophobic chain) was synthesized from cyanuric chloride, aliphatic amine, ethylenediamine, N,N'-dimethyl-1,3-propyldiamine and sodium 2-chloroethanesulfonate. The chemical structures of the prepared compounds were confirmed by FT-IR and 1 H NMR. The critical micelle concentrations (CMC) in aqueous solutions at 25°C were determined by surface tension method. The CMC value decreased with increasing length of the carbon chain. The CMC reached a minimum as low as 5 × 10 −5 mol · L −1 for C 16 -GSBS. The interfacial tensions (IFT) between Daqing crude oil and C n -GSBS surfactant solutions were also measured. The effects of the concentration of Na 2 CO 3 , the concentration and carbon chain length of C n -GSBS on the IFT of crude oil-water were investigated in detail. The results show that, for the aqueous surfactant system containing the weak base Na 2 CO 3 , oil-water interfacial tension can be reduced to 10 −2 mN m −1 orders of magnitude. The results also indicate that with the increase of surfactant concentration and the chain length, the oil-water interfacial tension decreased markedly, which indicates that C n -GSBS surfactants have a good interface activity. These surfactants are good candidates for weak base-surfactant-polymer EOR process.