To improve the surface properties in solution, a series of imidazolum Gemini surfactants with methylene spacer chains were synthesized. The structure of the target product is characterized by 1HNMR. The surface tension of imidazolum Gemini surfactants was measured at 25 ℃. The results show that the synthetic imidazolum Gemini surfactants are consistent with the target structure. As the number of carbon atoms of the hydrophobic group increases, the tendency of adsorption on the gas-liquid interface increases with the fixed length of the hydrophilic spacer. The critical micelle concentration and adsorption capacity decrease while the adsorption area and pc20 increase. The effect of the hydrophobic length on the surface tension is weak with the high surface activities. In addition, the shorter the hydrophilic spacer length of imidazolum Gemini surfactants is, the higher the adsorption and surface tension with the fixed length of the hydrophobic group.