In thin film multilayer along with total interface widths, study of individual interface widths of the constituent elements of the multilayer is important for the knowledge of diffusion mechanism and diffusion kinetics. Element specific Grazing Incidence X-ray Fluorescence (GIXRF) technique has been used to study the individual interface diffusion of Ni and Ti in the Ni/Ti multilayer. The above measurements yield similar results on the interface qualities of the multilayer as obtained from more widely used Grazing Incidence X-ray reflectivity (GIXRR) technique and give additional information regarding Ni and Ti diffusion separately which cannot be obtained from GIXRR. Ni-fluorescence and Ti-fluorescence GIXRF spectra of 10-bilayer Ni/Ti multilayer films are fitted simultaneously to find the interface widths of Ni and Ti at the Ni-on-Ti and Ti-on-Ni interfaces. The Error function distribution has been used to describe the concentration of elements at the interfaces. Further, the variation of these individual diffusion and individual concentration profile of elements has been studied with annealing of the multilayer. It has been shown that non-destructive and relatively simpler GIXRF technique can be used for elemental depth profiling of a multilayer very precisely, which otherwise can be obtained by using complicated destructive technique like atom probe tomography.