Abstract: The effects of different carbon chain length with Gaussian distribution of 9-ethyoxy-fatty alcohol(AE₉) on the surface adsorption, micelle formation were studied. Experimental results indicate that regular solution theory with nonideal miximg rule seems to be more reasonable than ideal mixing in calculating therm-odynamic parameters of this system. The efficiency and effectiveness of surface tension reduction and synergestic effect of mixed AE₉solution can be increased by adjusting properly the carbon chain length distribution of polyoxyethylenated fatty alcohols.