In this thesis the Moire’ Defelectometery technique is applied to the investigationrnof diffusion dynamics in transparent liquid mixtures.It describe the theoreticalrnanalysis for obtaining the magnitude of diffusion coefficient using moire’ fringernpatterns.The theoretical aspect of methods are presentes the relationship betweenrnthe moire’fringe shift and diffusion coefficient.Based on moire’ effect, the displacementrn(moire’ fringe shift position) can be used to calculate deflection angle of laserrnbeam,which is induced by the variation of refractive index.The physical and mathematicalrnmodel of laser moire’ defelectometery is presented in detail.rnIn diffusion of high concentration sugar solution the formation of dense layer abovernthe initial boundary of two liquids was observed. This may be related to so-calledrnbaro-diffusion effect- influence of gravity on diffusant molecules , that forms ,the uprnward motion of sugar molecules are balanced by gravity.rnKey Words : Moire’Deflectomrtery,Fringe Projection,Moire’Fringes ,Grating,rnMoire’Fringes, Index of Refraction, Moire’fringe shift