Densities of potassium aluminium sulphate have been measured in dimethyl sulphoxide (DMSO) + water, containing 0, 5, 10, 15, and 20 mass percent of DMSO, at different concentration and at 298.15, 303.15, 308.15 and 313.15 K. From the densities, apparent molar volumes have been derived. The apparent molar volume data have been analyzed using Masson equation. The limiting molar volumes, vф0, and Sv* slop are interpreted in terms of solute-solvent and solute-solute interactions respectively. The vф0 values vary with temperature as power series of temperature. Finally, the structure making/ breaking capacities of salts have been inferred from the Hepler’s criterion.