The composition and solubilization ability of microemulsion systems Tween (Tween 20, Tween 60, Tween 80)/1-butanol/decane/7.5 % NaCl solution at various oil/water mass ratios were studied. As oil/water mass ratios (α) increase, the solubility of the alcohol increases, and for the system containing Tween 60 or Tween 80, the mass fractions of the alcohol in the interfacial layer, A S , increase, whereas for the system containing Tween 20, the mass fractions of the alcohol in the interfacial layer, A S , decrease. Also, the solubilization ability ( SP ∗) of the microemulsion systems decreases. The solubilization ability of the microemulsion systems containing different Tween surfactants in descending order is Tween 60 > Tween 80 > Tween 20. The effects of alcohols and alkanes on the composition and solubilization abilities of microemulsion systems Tween/alcohol/alkane/NaCl solution were also investigated.