Abstract: The surface adsorption and micelle formation of the mixed aqueous solution of fluorocarbon and hydrocarbon chains nonionic surfactants (C₁₀F₁₉O(C₂H₄O)₉H and C₈H_l7C₆H₄O(C₃H₄O)₁₀H) have been investigated. The surface tension of the mixed solution has been determined by the drop-volume method.The results indicate that(1) there is no completely miscible micelle but essentially the individual micelle(C₁₀F₁₉O(C₃H₄O)₉H and(C₈H_l7C₆H₄O(C₃H₄O)₁₀H) in the mixed aqueous solution, (2) surface mole fractions calculated by both methods are essentially consistent with each other, (3) the molecular interaction parameters (βσ) are of positive values. All of these indicate the real existence of "mutual phobicity" between the fluorocarbon and hydrocarbon chains in the mixed system.