This thesis deals with detailed investigation of the transport properties of a ternary liquid mixture by light scattering technique. We have extended the theory of the light scattering experiment and its application to investigate diffusion processes for multicomponent mixture in the immediate vicinity of the liquid-liquid critical point and far from it. As a model system we have chosen of the strong non-ideal ternary liquid system glycerol + acetone + water. The main focus of this thesis is a theoretical investigation of transport properties of ternary liquid mixture in the hydrodynamic range and in the critical singularity field. Using this technique we determined both the static and the dynamic properties such as the correlation length, osmotic susceptibility, thermal diffusion and mass diffusion in the ternary GAW liquid mixture system in the vicinity of its critical solution point and far from it. Near the critical solution point both the correlation length and the generalized osmotic susceptibilities data can be described by simple scaling laws with three - dimensional Ising critical exponents. In this work a new theoretical extension of theory to ternary systems is developed. Far from the critical solution point in our system a coupling between two modes results in two characteristic relaxation times, which may be associated either with mass diffusion or thermal diffusion. In the vicinity of the critical solution point the dynamic light scattering measurements in our system reveal two and more hydrodynamic relaxation modes with well-separated characteristic relaxation times. From the autocorrelation functions we can experimentally determine at least two effective diffusivities D1 and D2. From theoretically prediction presented here, they may result from pure mass diffusion and pure thermal diffusion transport processes. When we compare the transport modes from light scattering with the Taylor dispersion measurements we find that only the slowest mode represents mass diffusion and this mode agrees very well with one of the eigenvalues of Fick’s diffusion matrix.