Ultrasonic velocities and densities have been measured for the dilute solutions of poly(ethylene glycol) of average molecular mass 400 g mol(-1) in benzene at different temperatures between 299 and 328 K. The experimental data have been used to compute the thermo-acoustical parameters namely isentropic compressibility (beta), intermolecular free length (L (f)), molar volume (V (m)), Schoff's available volume (V (a)(s)), acoustic impedance (Z), molar sound velocity (R (a)), and molar compressibility (W). Variation of these parameters with temperature of the sample and mole fraction of the solute in the solution, keeping one of the either constant has been discussed to collect the informations on molecular structure and intermolecular interactions.