In the present study, three Gemini cationic surfactants were prepared and characterized: N, Nʹ-((1,4-phenylenebis(oxy)) bis (2-oxoethane-2,1-diyl)) bis (N, N-dimethyl-3-octanamidopropan-1-aminium) (C1), N, Nʹ-((1,4-phenylenebis(oxy)) bis (2-oxoethane-2,1-diyl)) bis (3-dodecaneamido-N, N-dimethylpropan-1-aminium) (C2), N, Nʹ-((1,4-phenylenebis(oxy)) bis (2-oxoethane-2,1-diyl)) bis (N, N-dimethyl-3-palmitamidopropan-1-aminiccum) (C3). In water solutions, the CMC value of the prepared surfactants was detected by conductivity, surface tension, refractive index, molal volume, and spectrophotometric measurements. The effect of mixing of Gemini surfactant on CMC value was studied and discussed. Some surface properties of surfactants like excess surface concentration and minimum area per molecule were also calculated and discussed. Solvation thermodynamic parameters such as association constant, molal volume, and polarizability were also determined and discussed. The CMC value decreased from C1 to C3 due to an increase in the carbon chain length. Different physical methods show good agreement between CMC values detected by several techniques effect of mixing surfactants on CMC was also studied For example detecting CMC value for C1 when C2 and C3 are added at two concentrations, before and after the CMC values of the added surfactants, (0.00001M, 0.0003M) in water solution. and so on.