Phase behaviors and related physicochemical properties of the microemulsion systems containing hexadecyltrimethylammonium bromide + alcohol + alkane + brine were studied at various alkane/water volume ratios. The alcohol solubility (epsilon(B)) increases proportionally to the alkane/water ratio. Concurrently, the alcohol mass fraction in the interfacial layer (A(S)) increases, and the solubilization ability (SP*) of the system decreases. When the length of the carbon chain of the alkane molecules increases, the solubility of alcohol in the water and oil phases and the mass fraction of alcohol in the interfacial layer increase, while the solubilization ability of the microemulsion systems decreases.