Theoretical modeling equations are developed by extending regular associated solution model to predict the thermodynamic and structural properties of the liquid Tl−Na alloys at higher temperatures. The thermodynamic properties have been predicted by computing activities of unassociated monomers ( and ) and free energy of mixing ( ) at temperatures 673 K, 773 K, 873 K and 973 K. The structural properties have been predicted by computing concentration fluctuation in long wavelength limit ( ), short range order parameter ( ) and ratio of mutual to intrinsic diffusion coefficients ( ) at aforementioned temperatures. These properties have been then correlated with the modified Butler's model to predict the surface properties, such as surface concentrations of free monomers ( and ) and surface tension ( ) of the alloy at above mentioned temperatures.