The acoustic behaviour of aqueous dextran solution has been studied at 303K, 308K, 313K, 318K & 323K at 1MHz frequency in different concentration. Various parameters such as adiabatic compressibility, intermolecular free length, relaxation time, acoustic impedance, and Gibb’s free energy have been calculated using experimental determined values of ultrasonic velocity, density and viscosity. The variation of these parameters has been discussed in the light of solute and solvent interactions and structural arrangement of the molecules. The qualitative inter molecular elastic forces between the solute and solvate molecules are explained