A cationic gemini surfactant 10-2-10, 1,2-ethane bis(decyl dimethyl ammonium bromide) was synthesized, and the interactions in a mixture of the cationic gemini surfactant with a water-soluble polymer polyvinyl alcohol(PVA) were investigated by means of viscosity, electric conductivity, surface tension and ultraviolet spectrum measurements. The results showed that PVA displays viscosity behavior of polyelectrolyte-electroviscous effect in an aqueous solution with gemini surfactant 10-2-10 due to the molecular interaction between the polymer and the surfactant. The maximum UV absorption wavelength of polymer-surfactant solution shifted to higher wavelength compared with that of the surfactant, and the conductivity of polymer-surfactant solution increased with increase in concentration of PVA in a certain surfactant concentration. In addition, surface tension of gemini surfactant 10-2-10 solution decreased in the presence of PVA and its critical micelle concentration decreased from 5.9 mmol/L to 4.8 mmol/L in the presence of 1.25×10^-3 g/mL PVA.