In this paper,the surface activity of carboxylate gemini surfactants CGS-2 and the effect of the addition of NaCl on it were investigated,the effects of the liquid-solid ratio,absorption time and concentration on the surface adsorption of CGS-2 on the sandstone were studied.The results showed that,the critical micelle concentration of CGS-2 solution was 0.0223 mmol/L,which was 2—3 magnitude orders lower than that of the conventional surfactants,laurate sodium.The surface tension minimized to 29.49 mN/m.When adding a given mass of NaCl,the critical micelle concentration of CGS-2 decreased.The adsorption isotherm accorded with Langmuir mode.When the Liquid-solid ratio was 30∶ 1,and the adsorption equilibrium time was 36 h,the adsorption capacity of CGS-2 reached to the maximum on the sandstone surface at 25℃,being of 8.93 mg/g.